Automotive part made of polypropylene resin composition

ABSTRACT

An automobile part comprising a polypropylene resin composition, the polypropylene resin composition comprising a propylene homopolymer (A1), an elastomer (B) and an inorganic filler (C), or comprising a propylene block copolymer (A2) and an inorganic filler (C) optionally together with an elastomer (B), in specified proportions. The propylene homopolymer (A1), or the propylene homopolymer segment of the propylene block copolymer (A2) exhibits an MFR (230-C) of 20 to 300 g/10 min, a ratio of position irregular units derived from 2,1-insertion or 1,3-insertion of propylene monomer relative to all propylene structural units, determined from a  13 C-NMR spectrum, each of 0.2% or less, and an Mw/Mn, determined by GPC, of 1 to 3.

FIELD OF THE INVENTION

The present invention relates to an automobile part comprising apolypropylene resin composition.

BACKGROUND OF THE INVENTION

Polypropylene resins are used in daily use sundries, kitchen utensils,packing films, household electrical appliances, mechanical parts,electrical components, automobile parts and other various fields. Thepolypropylene resins are incorporated with various additives inconformity with the demanded performance. In particular, in the use inautomobile parts, compositions comprising a polypropylene resinincorporated with an α-olefin copolymer rubber and an inorganic fillersuch as talc are utilized in large quantities because molded articlesexhibit an excellent balance of rigidity and impact resistance.

Automobile parts for inner and outer trims are often formed by injectionmolding in view of productivity. When an injection molding of the abovepolypropylene resin composition is carried out, a plurality of periodicstriped patterns known as flow marks or tiger marks occur on the surfaceof injection molded articles in directions crossing with the directionof injection flow, which periodic striped patterns are conspicuous. Whenflow marks having occurred on the surface of a molded article areconspicuous, the appearance of the molded article would be degraded.Thus, according to necessity, coating or other measures would be carriedout in order to cause the flow marks to disappear. For eliminating theflow marks of the molded article obtained from the above polypropyleneresin composition or rendering the flow marks inconspicuous, variousmethods are employed. For example, a method in which use is made of ametal mold whose temperature can be varied and a resin is injected intothe metal mold maintained at a high temperature is employed. However,this method has a problem in production in that a special metal mold isneeded and in that the molding cycle is prolonged.

Moreover, with respect to automobile parts for inner trims, the surfacethereof is furnished with a pattern known as an emboss for the purposeof decorating the surface or lowering the surface gloss. This emboss isformed by transferring a pattern provided on the inside surface of themetal mold for injection molding to the surface of molded article at thetime of injection molding. When an injection molding of the abovepolypropylene resin composition is conducted, there would occur suchproblems that the transfer of emboss pattern provided on the insidesurface of the metal mold is poor to thereby fail to lower the gloss,and that the transferability is different between the vicinity of a gateof the metal mold and a position remote from the gate to thereby bringabout a gloss difference.

In the injection molding, pellets of solid resin composition are heatedand melted (plasticized) in a heated cylinder, and the molten resincomposition is injected and charged into a metal mold (cavity). Theheating and melting of the resin composition used to obtain an injectionmolded article in the subsequent molding cycle are carried out duringthe cooling after the completion of the injection and charging. Forshortening the molding cycle for obtaining an injection molded article,it is necessary to shorten the cooling time. There would be no problemif the heating and melting of resin composition needed in the subsequentinjection and charging can be completed during the shortened coolingtime. However, when the heating and melting cannot be completed duringthe cooling time, the subsequent injection and charging cannot beeffected. This causes shortening of the cooling time impracticable. Theabove polypropylene resin composition necessitates a prolongedheating/melting time (plasticization time) and disenables shortening ofthe cooling time. Therefore, the above polypropylene resin compositionhas a drawback in that the molding cycle cannot be shortened.

A composition comprising a polypropylene resin (propylene homopolymer,propylene block copolymer) produced in the presence of a metallocenecatalyst, an α-olefin copolymer rubber and an inorganic filler is knownas one described in Japanese Patent Laid-open Publication No.10(1998)-1573. However, in the production of the polypropylene resin inthe presence of a metallocene catalyst, 1,3-insertion or 2,1-insertionof propylene occurs in a proportion of about 1%. Thus, the crystallinityof the polypropylene resin is low, so that the melting point thereof isabout 150° C., which melting point is lower than 160° C. of thepolypropylene resin produced in the presence of a titanium catalyst.Further, the polypropylene resin produced in the presence of ametallocene catalyst is inferior to the polypropylene resin produced inthe presence of a titanium catalyst in the tensile strength properties,flexural strength properties, rigidity, etc. Accordingly, the mechanicalstrength properties of the composition comprising the polypropyleneresin produced in the presence of a metallocene catalyst, an α-olefincopolymer rubber and an inorganic filler are poor as compared with thoseof the composition comprising the polypropylene resin produced in thepresence of a titanium catalyst, an α-olefin copolymer rubber and aninorganic filler. Therefore, the former composition has not been put topractical use.

The inventors have made extensive and intensive studies with a viewtoward solving the above problems. As a result, it has been found thatthere is substantially no 1,3-insertion or 2,1-insertion of propylene inthe propylene homopolymer or propylene block copolymer produced in thepresence of a specified metallocene catalyst, so that the melting pointof the propylene homopolymer or propylene block copolymer is high and sothat the molded article thereof is excellent in the rigidity, tensilestrength properties and flexural strength properties. It has furtherbeen found that the polypropylene resin composition based on thepropylene homopolymer or propylene block copolymer exhibits excellentperformance as a composition for automobile part. The present inventionhas been completed on the basis of these findings.

It is an object of the present invention to solve the above problems ofthe prior art, specifically to provide an automobile part, especially aninjection molded automobile part, which is improved in flow marks andhas excellent appearance and emboss transfer.

It is another object of the present invention to provide an automobilepart, especially an injection molded automobile part, which has anexcellent balance of rigidity and impact resistance.

DISCLOSURE OF THE INVENTION

According to the first aspect of the present invention, there isprovided an automobile part comprising a polypropylene resincomposition, the polypropylene resin composition comprising 30 to 80% byweight of a propylene homopolymer (A1), 15 to 40% by weight of anelastomer (B) and 5 to 30% by weight of an inorganic filler (C),

wherein the propylene homopolymer (A1) exhibits:

(i) a melt flow rate (measured at 230° C. under a load of 2.16 kgaccording to ASTM D 1238) of 20 to 300 g/10 min,

(ii) a proportion of position irregular units derived from 2,1-insertionor 1,3-insertion of propylene monomer relative to all propylenestructural units, determined from a ¹³C-NMR spectrum, each of 0.2% orless, and

(iii) a molecular weight distribution (Mw/Mn), determined by gelpermeation chromatography (GPC), of 1 to 3.

According to the second aspect of the present invention, there isprovided an automobile part comprising a polypropylene resincomposition, the polypropylene resin composition comprising a propyleneblock copolymer (A2) and an inorganic filler (C) optionally togetherwith an elastomer (B), the propylene block copolymer (A2) comprisingpropylene homopolymer segment and propylene/α-olefin random copolymersegment,

wherein the propylene homopolymer segment of the propylene blockcopolymer (A2) exhibits:

(i) a melt flow rate (measured at 230° C. under a load of 2.16 kgaccording to ASTM D 1238) of 20 to 300 g/10 min,

(ii) a proportion of position irregular units derived from 2,1-insertionor 1,3-insertion of propylene monomer relative to all propylenestructural units, determined from a ¹³C-NMR spectrum, each of 0.2% orless, and

(iii) a molecular weight distribution (Mw/Mn), determined by gelpermeation chromatography (GPC), of 1 to 3,

and wherein, based on the total weight of the propylene block copolymer(A2), the elastomer (B) and the inorganic filler (C), in thepolypropylene resin composition, the propylene homopolymer segment ofthe propylene block copolymer (A2) is contained in an amount of 30 to80% by weight, the propylene/α-olefin random copolymer segment of thepropylene block copolymer (A2) plus the elastomer (B) is contained in atotal amount of 15 to 40% by weight, and the inorganic filler (C) iscontained in an amount of 5 to 30% by weight.

In the automobile parts comprising a polypropylene resin compositionaccording to the first and second aspects of the present invention, itis preferred that the elastomer (B) be at least one elastomer selectedfrom among a propylene/α-olefin random copolymer (B-1), anethylene/α-olefin random copolymer (B-2), anethylene/α-olefin/nonconjugated polyene random copolymer (B-3) and ahydrogenated block copolymer (B-4).

It is especially preferred that the inorganic filler (C) be talc.

Preferably, in cross fractionating chromatography (CFC) of thepolypropylene resin composition, a 100 to 135° C. eluate withorthodichlorobenzene exhibits a ratio (Mw/Mn) of weight averagemolecular weight (Mw) to number average molecular weight (Mn) of 1 to 3.

Moreover, it is especially preferred that the automobile part be aninjection molded article that, when reflectances (angle of incidence:90°, angle of reflection: 90° and area where measuring is performed: 4mmφ) are measured at intervals of 5 mm in a direction of injection flowover a length of 50 to 150 mm from a flow end, a reflectance differencebetween neighboring measuring points satisfies the formula:Δ reflectance difference≦0.5.

PREFERRED EMBODIMENTS OF THE INVENTION

The automobile part comprising a polypropylene resin compositionaccording to the present invention will be described in detail below.

In the automobile part comprising a polypropylene resin compositionaccording to the present invention, the polypropylene resin compositioncomprises a propylene homopolymer (A1), an elastomer (B) and aninorganic filler (C), or comprises a propylene block copolymer (A2) andan inorganic filler (C) optionally together with an elastomer (B).

Propylene Homopolymer (A1)

The propylene homopolymer (A1) for use in the present invention is acrystalline polypropylene resin characterized by exhibiting:

(i) a melt flow rate (MFR, measured at 230° C. under a load of 2.16 kgaccording to ASTM D 1238) of 20 to 300 g/10 min, preferably 20 to 250g/10 min, still preferably 30 to 220 g/10 min, and optimally 40 to 200g/10 min,

(ii) a proportion of position irregular units derived from 2,1-insertionor 1,3-insertion of propylene monomer relative to all propylenestructural units, determined from a ¹³C-NMR spectrum, each of 0.2% orless, preferably 0.1% or less, and still preferably 0.05% or less, and

(iii) a molecular weight distribution (Mw/Mn), determined by gelpermeation chromatography (GPC), of 1 to 3, preferably 1 to 2.5, andstill preferably 1 to 2.3.

Further, the propylene homopolymer (A1) preferably has the followingcharacteristics (iv), (v) and (vi).

(iv) The n-decane soluble content (% by weight of matter dissolved inn-decane when the propylene homopolymer has been treated with n-decaneat 150° C. for 2 hr and cooled to room temperature) of the propylenehomopolymer (A1) is 2% by weight or less, preferably 1% by weight orless.

(v) The pentad isotacticity, determined from a ¹³C-NMR spectrum, of thepropylene homopolymer (A1) is 90% or more, preferably 93% or more, andstill preferably 94% or more.

The isotactic pentad fraction (mmmm fraction) indicates the ratio ofpresence of isotactic chains to pentad units in the molecular chain ofpropylene block copolymer (A), as measured by means of ¹³C-NMR. That is,the isotactic pentad fraction (mmmm fraction) is the fraction ofpropylene monomer unit existing in the center of a chain consisting offive propylene monomer units continuously meso-bonded to each other.Specifically, the isotactic pentad fraction (mmmm fraction) is a valuecalculated as the fraction of mmmm peaks among all absorption peaks inthe methyl carbon region measured from a ¹³C-NMR spectrum.

(vi) In the measurement by means of a differential scanning calorimeter(DSC), it is generally preferred that the temperature (Tm) at themaximum peak position of the obtained endothermic curve be in the rangeof 155 to 170° C., especially 157 to 165° C., and still especially 158to 163° C.

The propylene homopolymer (A1) for use in the present invention isprepared, for example, in the presence of a specified metallocenecatalyst. A metallocene compound catalyst component for forming thismetallocene catalyst is represented by the following general formula (1)or (2):

wherein:

R³ is selected from among hydrocarbon groups and silicon-containinghydrocarbon groups;

R¹, R², R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², R¹³ and R¹⁴ may beidentical with or different from each other, and each thereof isselected from among a hydrogen atom, hydrocarbon groups andsilicon-containing hydrocarbon groups,

provided that, among the groups represented by R¹ to R¹², neighboringgroups may be bonded with each other to thereby form a ring, andprovided that, in the general formula (1), a group selected from thoseof R¹, R⁴, R⁵ and R¹² may be bonded with a group represented by R¹³ orR¹⁴ to thereby form a ring;

A represents a divalent hydrocarbon group having 2 to 20 carbon atoms,which may contain an unsaturated bond and/or an aromatic ring, providedthat A may contain two or more ring structures including a ring formedthereby with an atom represented by Y;

Y represents a carbon atom or a silicon atom;

M represents a metal selected from among those of the group 4 of theperiodic table;

j is an integer of 1 to 4; and

Q is selected from among halogen atoms, hydrocarbon groups, anionicligands and neutral ligands capable of coordination with a lone electronpair, provided that, when j is 2 or greater, Qs may be identical with ordifferent from each other.

Another metallocene compound catalyst component for use in the presentinvention consists of a metallocene compound represented by thefollowing general formula (1a) or (2a):

wherein:

R³ is selected from among hydrocarbon groups and silicon-containinghydrocarbon groups;

R¹, R², R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², R¹³ and R¹⁴ may beidentical with or different from each other, and each thereof isselected from among a hydrogen atom, hydrocarbon groups andsilicon-containing hydrocarbon groups,

provided that, with respect to the compound of the general formula (1a)wherein R³ represents a tert-butyl group or a trimethylsilyl group andwherein R¹³ and R¹⁴ simultaneously represent methyl or phenyl groups, R⁶and R¹¹ do not simultaneously represent hydrogen atoms, provided that,among the groups represented by R¹ to R¹², neighboring groups may bebonded with each other to thereby form a ring, and provided that, in thegeneral formula (1a), a group selected from among those of R¹, R⁴, R⁵and R¹² may be bonded with a group represented by R¹³ or R¹⁴ to therebyform a ring;

A represents a divalent hydrocarbon group having 2 to 20 carbon atoms,which may contain an unsaturated bond and/or an aromatic ring, providedthat A may contain two or more ring structures including a ring formedthereby with an atom represented by Y;

Y represents a carbon atom or a silicon atom;

M represents a metal selected from among those of the group 4 of theperiodic table;

j is an integer of 1 to 4; and

Q is selected from among halogen atoms, hydrocarbon groups, anionicligands and neutral ligands capable of coordination with a lone electronpair, provided that, when j is 2 or greater, Qs may be identical with ordifferent from each other.

Still another metallocene compound catalyst component consists of ametallocene compound represented by the following general formula (1b)or (2b):

wherein:

R²¹ and R²² may be identical with or different from each other, and eachthereof is selected from among hydrocarbon groups and silicon-containinghydrocarbon groups;

R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², R¹³ and R¹⁴ may be identical with ordifferent from each other, and each thereof is selected from among ahydrogen atom, hydrocarbon groups and silicon-containing hydrocarbongroups, provided that, among the groups represented by R⁵ to R¹²,neighboring groups may be bonded with each other to thereby form a ring;

A represents a divalent hydrocarbon group having 2 to 20 carbon atoms,which may contain an unsaturated bond and/or an aromatic ring, providedthat A may contain two or more ring structures including a ring formedthereby with an atom represented by Y;

M represents a metal selected from among those of the group 4 of theperiodic table;

Y represents a carbon atom or a silicon atom;

j is an integer of 1 to 4; and

Q is selected from among halogen atoms, hydrocarbon groups, anionicligands and neutral ligands capable of coordination with a lone electronpair, provided that, when j is 2 or greater, Qs may be identical with ordifferent from each other.

Preferred examples of the above hydrocarbon groups include an alkylgroup having 1 to 20 carbon atoms, an arylalkyl group having 7 to 20carbon atoms, an aryl group having 6 to 20 carbon atoms and an alkylarylgroup having 7 to 20 carbon atoms.

R³ may be a cyclic hydrocarbon group containing a heteroatom such assulfur or oxygen, such as a thienyl group or a furyl group.

For example, there can be mentioned hydrocarbon groups such as methyl,ethyl, n-propyl, isopropyl, 2-methylpropyl, 1,1-dimethylpropyl,2,2-dimethylpropyl, 1,1-diethylpropyl, 1-ethyl-1-methylpropyl,1,1,2,2-tetramethylpropyl, sec-butyl, tert-butyl, 1,1-dimethylbutyl,1,1,3-trimethylbutyl, neopentyl, cyclohexylmethyl, cyclohexyl,1-methyl-1-cyclohexyl, 1-adamantyl, 2-adamantyl, 2-methyl-2-adamantyl,menthyl, norbornyl, benzyl, 2-phenylethyl, 1-tetrahydronaphthyl,1-methyl-1-tetrahydronaphthyl, phenyl, naphthyl and tolyl.

Preferred examples of the above silicon-containing hydrocarbon groupsinclude an arylsilyl or alkylsilyl group having 1 to 4 silicon atoms andhaving 3 to 20 carbon atoms.

Specifically, there can be mentioned groups such as trimethylsilyl,tert-butyldimethylsilyl and triphenylsilyl.

R³ preferably represents a sterically bulky substituent, stillpreferably a substituent having 4 or more carbon atoms.

In the above general formula (1) or (2), R¹, R², R⁴, R⁵, R⁶, R⁷, R⁸, R⁹,R¹⁰, R¹¹, R¹², R¹³ and R¹⁴ may be identical with or different from eachother, and each thereof is selected from among a hydrogen atom,hydrocarbon groups and silicon-containing hydrocarbon groups. Preferredexamples of the hydrocarbon groups and silicon-containing hydrocarbongroups are as mentioned above.

With respect to R¹ to R⁴ as substituents of the cyclopentadienyl ring,neighboring substituents may be bonded with each other to thereby form aring. Examples of such substituted cyclopentadienyl groups includeindenyl, 2-methylindenyl, tetrahydroindenyl, 2-methyltetrahydroindenyland 2,4,4-trimethyltetrahydroindenyl.

With respect to R⁵ to R¹² as substituents of the fluorene ring,neighboring substituents may be bonded with each other to thereby form aring. Examples of such substituted fluorenyl groups includebenzofluorenyl, dibenzofluorenyl, octahydrodibenzofluorenyl andoctamethyloctahydrodibenzofluorenyl.

With respect to R⁵ to R¹² as substituents of the fluorene ring, it ispreferred that these substituents be symmetrical from the viewpoint ofeasiness in synthesis. That is, it is preferred that the group R⁵ beidentical with the group R¹², the group R⁶ with the group R¹¹, the groupR⁷ with the group R¹⁰, and the group R⁸ with the group R⁹. It isespecially preferred to employ nonsubstituted fluorene,3,6-disubstituted fluorene, 2,7-disubstituted fluorene or2,3,6,7-tetrasubstituted fluorene. The 3-position, 6-position,2-position and 7-position of the fluorene ring correspond to R⁷, R¹⁰, R⁶and R¹¹, respectively.

In the above general formula (1) or (2), Y represents a carbon atom or asilicon atom.

In the metallocene compound of the above general formula (1), R¹³ andR¹⁴ are bonded with Y to thereby form a substituted methylene group orsubstituted silylene group as a bridging moiety. Preferably, thebridging moiety can be, for example, methylene, dimethylmethylene,diethylmethylene, diisopropylmethylene, methyl-tert-butylmethylene,di-tert-butylmethylene, dicyclohexylmethylene,methylcyclohexylmethylene, methylphenylmethylene, diphenylmethylene,methylnaphthylmethylene, dinaphthylmethylene, or dimethylsilylene,diisopropylsilylene, methyl-tert-butylsilylene, dicyclohexylsilylene,methylcyclohexylsilylene, methylphenylsilylene, diphenylsilylene,methylnaphthylsilylene or dinaphthylsilylene.

In the metallocene compound of the above general formula (1), asubstituent selected from among those of R¹, R⁴, R⁵ and R¹² may bebonded with a substituent represented by R¹³ or R¹⁴ of the bridgingmoiety to thereby form a ring. As examples of such structures,structures wherein R¹ and R¹⁴ are bonded with each other to thereby forma ring will be shown below. In the metallocene compound of the followinggeneral formula (1c), the bridging moiety and the cyclopentadienyl groupjoin together to thereby form a tetrahydropentalene skeleton. In themetallocene compound of the following general formula (1d), the bridgingmoiety and the cyclopentadienyl group join together to thereby form atetrahydroindenyl skeleton. Likewise, the bridging moiety may be bondedwith the fluorenyl group to thereby form a ring.

In the metallocene compound of the above general formula (2), Arepresents a divalent hydrocarbon group having 2 to 20 carbon atoms,which may contain an unsaturated bond and/or an aromatic ring. Y isbonded with this A to thereby form, for example, a cycloalkylidene groupor a cyclomethylenesilylene group.

A may contain two or more ring structures including a ring formedthereby with Y.

Preferred examples thereof include cyclopropylidene, cyclobutylidene,cyclopentylidene, cyclohexylidene, cycloheptylidene,bicyclo[3,3,1]nonylidene, norbornylidene, adamantylidene,tetrahydronaphthylidene, dihydroindanylidene, cyclodimethylenesilylene,cyclotrimethylenesilylene, cyclotetramethylenesilylene,cyclopentamethylenesilylene, cyclohexamethylenesilylene andcycloheptamethylenesilylene.

In the above general formula (1) or (2), M represents a metal selectedfrom among those of the group 4 of the periodic table. For example, itcan be titanium, zirconium or hafnium.

In the above general formula (1) or (2), j is an integer of 1 to 4.

In the above general formula (1) or (2), Q is selected from amonghalogen atoms, hydrocarbon groups having 1 to 20 carbon atoms, anionicligands, and neutral ligands capable of coordination with a loneelectron pair. When j is 2 or greater, Qs may be identical with ordifferent from each other.

Examples of the halogen atoms include fluorine, chlorine, bromine andiodine. Examples of the hydrocarbon groups are as aforementioned.

Examples of the anionic ligands include alkoxy groups such as methoxy,tert-butoxy and phenoxy; carboxylate groups such as acetate andbenzoate; and sulfonate groups such as mesylate and tosylate.

Examples of the neutral ligands capable of coordination with a loneelectron pair include organophosphorus compounds such astrimethylphosphine, triethylphosphine, triphenylphosphine anddiphenylmethylphosphine; and ethers such as tetrahydrofuran, diethylether, dioxane and 1,2-dimethoxyethane.

It is preferred that at least one of Qs be a halogen or an alkyl group.

Examples of the metallocene compounds of general formula (1) or (2)according to the present invention will be set forth below.

First, the ligand structure, excluding MQj (metal portion), of eachmetallocene compound will be divided into three moieties, namely, Cp(cyclopentadienyl ring portion), Bridge (bridging portion) and Flu(fluorenyl ring portion) for the purpose of indication on tables.Specific examples of the structures of individual moieties and specificexamples of the ligand structures obtained by combinations thereof willbe set forth below.

Specific Examples of Cp

a1

a2

a3

a4

a5

a6

a7

a8

a9

a10

a11

a12

a13

a14

a15

a16

a17

a18

a19

a20

a21

a22

a23

a24

a25Specific Examples of Bridge

b1

b2

b3

b4

b5

b6

b7

b8

b9

b10

b11

b12

b13

b14

b15Specific Examples of Flu

c1

c2

c3

c4

c5

c6

c7

As a specific example of metallocene compound having a preferred ligandstructure, there can be mentioned the compound of the formula:

MQj can be, for example, any of ZrCl₂, ZrBr₂, ZrMe₂, Zr(OTs)₂, Zr(OMs)₂,Zr(OTf)₂, TiCl₂, TiBr₂, TiMe₂, Ti(OTs)₂, Ti(OMs)₂, Ti(OTf)₂, HfCl₂,HfBr₂, HfMe₂, Hf(OTs)₂, Hf(OMs)₂ and Hf(OTf)₂. In these, Ts represents ap-toluenesulfonyl group; Ms represents a methanesulfonyl group; and Tfrepresents a trifluoromethanesulfonyl group.

Further, as metallocene compounds wherein a substituent of the Cp ringis bonded with a substituent of the bridging portion to thereby form aring, there can be mentioned compounds of the formulae:

Preferred examples of the metallocene compounds of general formula (1)or (2) according to the present invention include:

metallocene compound of the general formula (1) wherein each of R¹, R¹³and R¹⁴ represents methyl; R³ represents tert-butyl; each of R², R⁴, R⁵,R⁷, R⁸, R⁹, R¹⁰ and R¹² represents hydrogen; each of R⁶ and R¹¹represents tert-butyl; M represents zirconium; Y represents carbon; Qrepresents chlorine; and j is 2;

metallocene compound of the general formula (1) wherein each of R¹³ andR¹⁴ represents methyl; R³ represents 1-methyl-1-cyclohexyl; each of R¹,R², R⁴, R⁵, R⁶, R⁸, R⁹, R¹¹ and R¹² represents hydrogen; each of R⁷ andR¹⁰ represents tert-butyl; M represents zirconium; Y represents carbon;Q represents chlorine; and j is 2;

metallocene compound of the general formula (1) wherein each of R¹³ andR¹⁴ represents methyl; R³ represents tert-butyl; each of R¹, R², R⁴, R⁵,R⁸, R⁹ and R¹² represents hydrogen; R⁶ and R⁷ are bonded with each otherto thereby form a ring as represented by the formula—(C(CH₃)₂CH₂CH₂C(CH₃)₂)—; R¹⁰ and R¹¹ are bonded with each other tothereby form a ring as represented by the formula—(C(CH₃)₂CH₂CH₂C(CH₃)₂)—; M represents zirconium; Y represents carbon; Qrepresents chlorine; and j is 2;

metallocene compound of the general formula (1) wherein each of R¹³ andR¹⁴ represents methyl; R³ represents trimethylsilyl; each of R¹, R², R⁴,R⁵, R⁸, R⁹ and R¹² represents hydrogen; R⁶ and R⁷ are bonded with eachother to thereby form a ring as represented by the formula—(C(CH₃)₂CH₂CH₂C(CH₃)₂)—; R¹⁰ and R¹¹ are bonded with each other tothereby form a ring as represented by the formula—(C(CH₃)₂CH₂CH₂C(CH₃)₂)—; M represents zirconium; Y represents carbon; Qrepresents chlorine; and j is 2;

metallocene compound of the general formula (1) wherein each of R¹³ andR¹⁴ represents methyl; R³ represents 1,1-dimethylpropyl; each of R¹, R²,R⁴, R⁵, R⁶, R⁸, R⁹, R¹¹ and R¹² represents hydrogen; each of R⁷ and R¹⁰represents tert-butyl; M represents zirconium; Y represents carbon; Qrepresents chlorine; and j is 2;

metallocene compound of the general formula (1) wherein each of R¹³ andR¹⁴ represents methyl; R³ represents 1-ethyl-1-methylpropyl; each of R¹,R², R⁴, R⁵, R⁶, R⁸, R⁹, R¹¹ and R¹² represents hydrogen; each of R⁷ andR¹⁰ represents tert-butyl; M represents zirconium; Y represents carbon;Q represents chlorine; and j is 2;

metallocene compound of the general formula (1) wherein each of R¹³ andR¹⁴ represents methyl; R³ represents 1,1,3-trimethylbutyl; each of R¹,R², R⁴, R⁵, R⁶, R⁸, R⁹, R¹¹ and R¹² represents hydrogen; each of R⁷ andR¹⁰ represents tert-butyl; M represents zirconium; Y represents carbon;Q represents chlorine; and j is 2;

metallocene compound of the general formula (1) wherein each of R¹³ andR¹⁴ represents methyl; R³ represents 1,1-dimethylbutyl; each of R¹, R²,R⁴, R⁵, R⁶, R⁸, R⁹, R¹¹ and R¹² represents hydrogen; each of R⁷ and R¹⁰represents tert-butyl; M represents zirconium; Y represents carbon; Qrepresents chlorine; and j is 2;

metallocene compound of the general formula (1) wherein each of R¹³ andR¹⁴ represents methyl; R³ represents tert-butyl; each of R¹, R², R⁴, R⁵,R⁷, R⁸, R⁹, R¹⁰ and R¹² represents hydrogen; each of R⁶ and R¹¹represents tert-butyl; M represents zirconium; Y represents carbon; Qrepresents chlorine; and j is 2;

metallocene compound of the general formula (1) wherein each of R³, R¹³and R¹⁴ represents phenyl; each of R¹, R², R⁴, R⁵, R⁸, R⁹ and R¹²represents hydrogen; R⁶ and R⁷ are bonded with each other to therebyform a ring as represented by the formula —(C(CH₃)₂CH₂CH₂C(CH₃)₂)—; R¹⁰and R¹¹ are bonded with each other to thereby form a ring as representedby the formula —(C(CH₃)₂CH₂CH₂C(CH₃)₂)—; M represents zirconium; Yrepresents carbon; Q represents chlorine; and j is 2;

metallocene compound of the general formula (1) wherein R³ representstrimethylsilyl; each of R¹³ and R¹⁴ represents phenyl; each of R¹, R²,R⁴, R⁵, R⁸, R⁹ and R¹² represents hydrogen; R⁶ and R⁷ are bonded witheach other to thereby form a ring as represented by the formula—(C(CH₃)₂CH₂CH₂C(CH₃)₂)—; R¹⁰ and R¹¹ are bonded with each other tothereby form a ring as represented by the formula—(C(CH₃)₂CH₂CH₂C(CH₃)₂)—; M represents zirconium; Y represents carbon; Qrepresents chlorine; and j is 2;

metallocene compound of the general formula (1) wherein R¹³ representsmethyl; R¹⁴ represents phenyl; R³ represents tert-butyl; each of R¹, R²,R⁴, R⁵, R⁶, R⁸, R⁹, R¹¹ and R¹² represents hydrogen; each of R⁷ and R¹⁰represents tert-butyl; M represents zirconium; Y represents carbon; Qrepresents chlorine; and j is 2;

metallocene compound of the general formula (1) wherein each of R¹³ andR¹⁴ represents ethyl; R³ represents tert-butyl; each of R¹, R², R⁴, R⁵,R⁶, R⁸, R⁹, R¹¹ and R¹² represents hydrogen; each of R⁷ and R¹⁰represents tert-butyl; M represents zirconium; Y represents carbon; Qrepresents chlorine; and j is 2;

metallocene compound of the general formula (2) wherein R¹ representsmethyl; R³ represents tert-butyl; each of R², R⁴, R⁵, R⁶, R⁷, R⁸, R⁹,R¹⁰, R¹¹ and R¹² represents hydrogen; M represents zirconium; Yrepresents carbon; Q represents chlorine; j is 2; and A represents—(CH₂)₅—;

metallocene compound of the general formula (2) wherein R¹ representsmethyl; R³ represents tert-butyl; each of R², R⁴, R⁵, R⁶, R⁸, R⁹, R¹¹and R¹² represents hydrogen; each of R⁷ and R¹⁰ represents tert-butyl; Mrepresents zirconium; Y represents carbon; Q represents chlorine; j is2; and A represents —(CH₂)₅—;

metallocene compound of the general formula (2) wherein R³ representstrimethylsilyl; each of R¹, R², R⁴, R⁵, R⁷, R⁸, R⁹, R¹⁰ and R¹²represents hydrogen; each of R⁶ and R¹¹ represents tert-butyl; Mrepresents zirconium; Y represents carbon; Q represents chlorine; j is2; and A represents —(CH₂)₅—;

metallocene compound of the general formula (2) wherein R³ representstrimethylsilyl; each of R¹, R², R⁴, R⁵, R⁶, R⁸, R⁹, R¹¹ and R¹²represents hydrogen; each of R⁷ and R¹⁰ represents tert-butyl; Mrepresents zirconium; Y represents carbon; Q represents chlorine; j is2; and A represents —(CH₂)₅—;

metallocene compound of the general formula (2) wherein R³ representstert-butyl; each of R¹, R², R⁴, R⁵, R⁶, R⁸, R⁹, R¹¹ and R¹² representshydrogen; each of R⁷ and R¹⁰ represents tert-butyl; M representszirconium; Y represents carbon; Q represents chlorine; j is 2; and Arepresents —(CH₂)₄—;

metallocene compound of the general formula (2) wherein R³ represents1,1-dimethylpropyl; each of R¹, R², R⁴, R⁵, R⁶, R⁸, R⁹, R¹¹ and R¹²represents hydrogen; each of R⁷ and R¹⁰ represents tert-butyl; Mrepresents zirconium; Y represents carbon; Q represents chlorine; j is2; and A represents —(CH₂)₅—;

metallocene compound of the general formula (2) wherein R³ representstert-butyl; each of R¹, R², R⁴, R⁵, R⁸, R⁹ and R¹² represents hydrogen;R⁶ and R⁷ are bonded with each other to thereby form a ring asrepresented by the formula —(C(CH₃)₂CH₂CH₂C(CH₃)₂)—; R¹⁰ and R¹¹ arebonded with each other to thereby form a ring as represented by theformula —(C(CH₃)₂CH₂CH₂C(CH₃)₂)—; M represents zirconium; Y representscarbon; Q represents chlorine; j is 2; and A represents —(CH₂)₄—;

metallocene compound of the general formula (1) wherein each of R¹, R¹³and R¹⁴ represents methyl; R³ represents tert-butyl; each of R², R⁴, R⁵,R⁶, R⁸, R⁹, R¹¹ and R¹² represents hydrogen; each of R⁷ and R¹⁰represents tert-butyl; M represents zirconium; Y represents carbon; Qrepresents chlorine; and j is 2;

metallocene compound of the general formula (1) wherein each of R¹³ andR¹⁴ represents methyl; R³ represents tert-butyl; each of R¹, R², R⁴, R⁵,R⁶, R⁸, R⁹, R¹¹ and R¹² represents hydrogen; each of R⁷ and R¹⁰represents tert-butyl; M represents zirconium; Y represents carbon; Qrepresents chlorine; and j is 2;

metallocene compound of the general formula (1) wherein each of R¹, R¹³and R¹⁴ represents methyl; R³ represents tert-butyl; each of R², R⁴, R⁵,R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹ and R¹² represents hydrogen; M representszirconium; Y represents carbon; Q represents chlorine; and j is 2;

metallocene compound of the general formula (1) wherein each of R¹³ andR¹⁴ represents methyl; R³ represents trimethylsilyl; each of R¹, R², R⁴,R⁵, R⁶, R⁸, R⁹, R¹¹ and R¹² represents hydrogen; each of R⁷ and R¹⁰represents tert-butyl; M represents zirconium; Y represents carbon; Qrepresents chlorine; and j is 2; and

metallocene compound of the general formula (1) wherein each of R¹³ andR¹⁴ represents phenyl; R³ represents trimethylsilyl; each of R¹, R², R⁴,R⁵, R⁶, R⁸, R⁹, R¹¹ and R¹² represents hydrogen; each of R⁷ and R¹⁰represents tert-butyl; M represents zirconium; Y represents carbon; Qrepresents chlorine; and j is 2.

These metallocene compounds can be used individually or in combination.These metallocene compounds can be used in a form on a particulatesupport.

As the particulate support, there can be employed an inorganic supportsuch as SiO₂, Al₂O₃, B₂O₃, MgO, ZrO₂, CaO, TiO₂, ZnO, SnO₂, BaO or ThO,or an organic support such as polyethylene, propylene block copolymer,poly-1-butene, poly-4-methyl-1-pentene or styrene/divinylbenzenecopolymer. These particulate supports can be used individually or incombination.

In the present invention, an aluminoxane can be used as a co-catalystfor the above metallocene catalyst. As known in the art to which thepresent invention pertains, the aluminoxane can be produced by, forexample, the following methods.

(1) One method comprises adding an organoaluminum compound such as atrialkylaluminum to a hydrocarbon medium suspension of a compoundcontaining an adsorbed water or a salt containing water ofcrystallization, for example, magnesium chloride hydrate, copper sulfatehydrate, aluminum sulfate hydrate, nickel sulfate hydrate or cerium (I)chloride hydrate to thereby effect a reaction thereof.

(2) Another method comprises causing water, ice or steam to directly acton an organoaluminum compound such as a trialkylaluminum in a mediumsuch as benzene, toluene, ethyl ether or tetrahydrofuran.

(3) Still another method comprises reacting an organic tin oxide such asdimethyltin oxide or dibutyltin oxide, with an organoaluminum compoundsuch as a trialkylaluminum, in a medium such as decane, benzene ortoluene.

The organoaluminum compound for use in the preparation of an aluminoxanecan be, for example, any of trialkylaluminums such as trimethylaluminum,triethylaluminum, tripropylaluminum, triisopropylaluminum,tri-n-butylaluminum, triisobutylaluminum, tri-sec-butylaluminum,tri-tert-butylaluminum, tripentylaluminum, trihexylaluminum,trioctylaluminum and tridecylaluminum; tricycloalkylaluminums such astricyclohexylaluminum and tricyclooctylaluminum; dialkylaluminum halidessuch as dimethylaluminum chloride, diethylaluminum chloride,diethylaluminum bromide and diisobutylaluminum chloride; dialkylaluminumhydrides such as diethylaluminum hydride and diisobutylaluminum hydride;dialkylaluminum alkoxides such as dimethylaluminum methoxide anddiethylaluminum ethoxide; and dialkylaluminum aryloxides such asdiethylaluminum phenoxide. Of these, trialkylaluminums andtricycloalkylaluminums are preferred. Trimethylaluminum is especiallypreferred.

As the organoaluminum compound for use in the preparation of analuminoxane, there can be employed an isoprenylaluminum.

The solvent for use in an aluminoxane solution or suspension can be ahydrocarbon solvent, for example, an aromatic hydrocarbon such asbenzene, toluene, xylene, cumene or cymene; an aliphatic hydrocarbonsuch as pentane, hexane, heptane, octane, decane, dodecane, hexadecaneor octadecane; an alicyclic hydrocarbon such as cyclopentane,cyclohexane, cyclooctane or methylcyclopentane; a petroleum fractionsuch as gasoline, kerosene or gas oil; or a halide, for example, achloride or bromide of the above aromatic hydrocarbon, aliphatichydrocarbon or alicyclic hydrocarbon.

In addition, use can be made of an ether such as ethyl ether ortetrahydrofuran. Of these solvents, the aromatic hydrocarbon andaliphatic hydrocarbon are preferred.

The organoaluminum oxy compound may contain a small amount of acomponent consisting of an organic compound of a metal other thanaluminum. As examples of ionized ionic compounds, there can be mentioneda Lewis acid, an ionic compound, a borane compound and a carboranecompound.

As the Lewis acid, there can be mentioned a compound of the formula BR₃,wherein R represents a phenyl group unsubstituted or substituted with afluorine atom, a methyl group or a trifluoromethyl group, or representsa fluorine atom. This compound can be, for example, trifluoroboron,triphenylboron, tris(4-fluorophenyl)boron,tris(3,5-difluorophenyl)boron, tris(4-fluoromethylphenyl)boron,tris(pentafluorophenyl)boron, tris(p-tolyl)boron, tris(o-tolyl)boron ortris(3,5-dimethylphenyl)boron.

As the ionic compound, there can be mentioned, for example, a trialkylsubstituted ammonium salt, an N,N-dialkylanilinium salt, adialkylammonium salt or a triarylphosphonium salt. Specifically, thetrialkyl substituted ammonium salt can be, for example,triethylammoniumtetra(phenyl)boron, tripropylammoniumtetra(phenyl)boronor tri(n-butyl)ammoniumtetra(phenyl)boron. The dialkylammonium salt canbe, for example, di(1-propyl)ammoniumtetra(pentafluorophenyl)boron ordicyclohexylammoniumtetra(phenyl)boron. As other ionic compounds, therecan be mentioned, for example, triphenylcarbeniumtetrakis(pentafluorophenyl) borate, N,N-dimethylanilinium tetrakis(pentafluorophenyl) borate and ferrocenium tetra(pentafluorophenyl)borate.

As the borane compound, there can be mentioned, for example, decaborane(14), bis[tri(n-butyl)ammonium]nonaborate,bis[tri(n-butyl)ammonium]decaborate, or a salt of metal borane anionsuch as bis[tri(n-butyl)ammonium]bis(dodecahydridododecaborate) nickelicacid (III) salt.

As the carborane compound, there can be mentioned, for example,4-carbanonaborane (14), 1,3-dicarbanonaborane (13), or a salt of metalcarborane anion such asbis[tri(n-butyl)ammonium]bis(undecahydrido-7-carbaundecaborate) nickelicacid (IV) salt.

These ionized ionic compounds can be used individually or incombination. The above organoaluminum oxy compounds and ionized ioniccompounds can be used in a form on the above particulate support.

At the time of preparing this catalyst, the following organoaluminumcompound may be used in combination with the organoaluminum oxy compoundor ionized ionic compound.

A compound having at least one Al-carbon bond in its molecule can beused as the organoaluminum compound. As this compound, there can bementioned, for example, an organoaluminum compound of the generalformula:(R¹)mAl(O(R²))nHpXq

wherein R¹ and R² may be identical with or different from each other,and each thereof represents a hydrocarbon group generally having 1 to15, preferably 1 to 4, carbon atoms; X represents a halogen atom; and m,n, p and q are numbers satisfying the relationships 0<m≦3, 0≦n<3, 0≦p<3and 0≦q<3, respectively, provided that m+n+p+q=3.

The propylene homopolymer (A1) for use in the present invention can beprepared by homopolymerization of propylene in the presence of the abovemetallocene catalyst.

In the process for producing the propylene homopolymer (A1), thepolymerization is generally performed at about −50 to 200° C.,preferably about 50 to 100° C., under atmospheric pressure to 100kg/cm², preferably about 2 to 50 kg/cm². The polymerization of propylenecan be performed by any of batch, semicontinuous and continuousprocesses.

Propylene Block Copolymer (A2)

The propylene block copolymer (A2) for use in the present invention is ablock copolymer comprising propylene homopolymer segment andpropylene/α-olefin random copolymer segment. The α-olefin content ofpropylene block copolymer (A2) as a whole is in the range of 1 to 40% byweight, preferably 3 to 30% by weight.

The propylene block copolymer (A2) for use in the present inventioncomprises propylene homopolymer segment which is insoluble in n-decaneat room temperature, optionally together with polyethylene segment, andpropylene/α-olefin random copolymer segment which is soluble in n-decaneat room temperature.

The propylene homopolymer segment of the propylene block copolymer (A2)for use in the present invention is characterized by having:

(i) a melt flow rate (MFR, measured at 230° C. under a load of 2.16 kgaccording to ASTM D 1238) of 20 to 300 g/10 min, preferably 20 to 250g/10 min, still preferably 30 to 220 g/10 min, and optimally 40 to 200g/10 min,

(ii) a proportion of position irregular units derived from 2,1-insertionor 1,3-insertion of propylene monomer relative to all propylenestructural units, determined from a ¹³C-NMR spectrum, each of 0.2% orless, preferably 0.1% or less, and still preferably 0.05% or less, and

(iii) a molecular weight distribution (Mw/Mn), determined by gelpermeation chromatography (GPC), of 1 to 3, preferably 1 to 2.5, andstill preferably 1 to 2.3.

Further, the propylene homopolymer segment preferably has the followingcharacteristics (iv), (v) and (vi).

(iv) The n-decane soluble content (% by weight of matter dissolved inn-decane when the propylene homopolymer has been treated with n-decaneat 150° C. for 2 hr and cooled to room temperature) of the propylenehomopolymer segment is 2% by weight or less, preferably 1% by weight orless.

(v) The pentad isotacticity, determined from a ¹³C-NMR spectrum, of thepropylene homopolymer segment is 90% or more, preferably 93% or more,and still preferably 95% or more.

The isotactic pentad fraction (mmmm fraction) indicates the ratio ofpresence of isotactic chains to pentad units in the molecular chain ofpropylene block copolymer (A2), as measured by means of ¹³C-NMR. Thatis, the isotactic pentad fraction (mmmm fraction) is the fraction ofpropylene monomer unit existing in the center of a chain consisting offive propylene monomer units continuously meso-bonded to each other.Specifically, the isotactic pentad fraction (mmmm fraction) is a valuecalculated as the fraction of mmmm peaks among all absorption peaks inthe methyl carbon region, measured from a ¹³C-NMR spectrum.

(vi) In the measurement by means of a differential scanning calorimeter(DSC), it is generally preferred that the temperature (Tm) at themaximum peak position of the obtained endothermic curve be in the rangeof 155 to 170° C., especially 155 to 165° C., and still especially 157to 163° C.

It is preferred that the propylene block copolymer (A2) for use in thepresent invention contain a component which is soluble in n-decane atroom temperature, namely, propylene/α-olefin random copolymer segment inan amount of 1 to 40% by weight, especially 3 to 30% by weight, stillespecially 5 to 25% by weight, and yet still especially 5 to 15% byweight, based on the weight of propylene block copolymer (A2).

The component soluble in n-decane at room temperature of the propyleneblock copolymer (A2) preferably contains units derived from an a-olefinother than propylene in an amount of 30 to 60 mol %, still preferably 35to 55 mol %.

The above α-olefin other than propylene is, for example, an α-olefinother than propylene having 2 to 20 carbon atoms, such as ethylene,1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene,1-dodecene, 1-hexadecene or 4-methyl-1-pentene.

The melt flow rate (MFR, measured at 230° C. under a load of 2.16 kgaccording to ASTM D 1238) of the propylene block copolymer (A2) isgenerally in the range of 10 to 150 g/10 min, preferably 20 to 120 g/10min, still preferably 30 to 100 g/10 min, and optimally 40 to 90 g/10min.

The propylene block copolymer (A2) for use in the present invention isprepared with the use of, for example, the specified metallocenecatalyst described hereinbefore with respect to the propylenehomopolymer (A1).

The propylene block copolymer (A2) for use in the present invention canbe prepared by carrying out, in the presence of the above metallocenecatalyst, a polymerization of propylene to thereby form propylenehomopolymer segment and a copolymerization of ethylene and propylene tothereby form ethylene/propylene copolymer segment in an arbitrarysequence.

In the process for producing the propylene block copolymer (A2), thepolymerization is generally performed at about −50 to 200° C.,preferably about 50 to 100° C., under atmospheric pressure to 100kg/cm², preferably about 2 to 50 kg/cm². The (co)polymerization ofpropylene can be performed by any of batch, semicontinuous andcontinuous processes.

Elastomer (B)

The elastomer (B) for use in the present invention can be any of apropylene/α-olefin random copolymer (B-1), an ethylene/α-olefin randomcopolymer (B-2), an ethylene/α-olefin/nonconjugated polyene randomcopolymer (B-3), a hydrogenated block copolymer (B-4), other elasticpolymers and mixtures of these.

The above propylene/α-olefin random copolymer (B-1) is a randomcopolymer rubber of propylene and ethylene or an α-olefin having 4 to 20carbon atoms.

The α-olefin having 4 to 20 carbon atoms can be, for example, any of1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene,1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene and 1-eicosene. Theseα-olefins and ethylene can be used individually or in combination. Amongthese, ethylene is especially preferably employed.

In the propylene/α-olefin random copolymer (B-1), it is preferred thatthe molar ratio of propylene to α-olefin (propylene/α-olefin) be in therange of 90/10 to 55/45, especially 80/20 to 55/45.

The melt flow rate (MFR, measured at 230° C. under a load of 2.16 kgaccording to ASTM D 1238) of the propylene/α-olefin random copolymer(B-1) is preferably 0.1 g/10 min or greater, still preferably in therange of 0.3 to 20 g/10 min.

The above ethylene/α-olefin random copolymer (B-2) is a random copolymerrubber of ethylene and an α-olefin having 3 to 20 carbon atoms.

The α-olefin having 3 to 20 carbon atoms can be, for example, any ofpropylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene,1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene and1-eicosene. These α-olefins can be used individually or in combination.Among these, propylene, 1-butene, 1-hexene and 1-octene are especiallypreferably employed.

In the ethylene/α-olefin random copolymer (B-2), it is preferred thatthe molar ratio of ethylene to α-olefin (ethylene/α-olefin) be in therange of 95/5 to 60/40, especially 90/10 to 70/30.

The melt flow rate (MFR, measured at 230° C. under a load of 2.16 kgaccording to ASTM D 1238) of the ethylene/α-olefin random copolymer(B-2) is preferably 0.1 g/10 min or greater, still preferably in therange of 0.3 to 20 g/10 min.

The above ethylene/α-olefin/nonconjugated polyene random copolymer (B-3)is a random copolymer rubber of ethylene, an α-olefin having 3 to 20carbon atoms and a nonconjugated polyene.

Examples of suitable α-olefins each having 3 to 20 carbon atoms are asmentioned above.

The nonconjugated polyene can be, for example, any of:

cyclic dienes such as 5-ethylidene-2-norbornene,5-propylidene-5-norbornene, dicyclopentadiene, 5-vinyl-2-norbornene,5-methylene-2-norbornene, 5-isopropylidene-2-norbornene andnorbornadiene;

chain nonconjugated dienes such as 1,4-hexadiene,4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 5-methyl-1,5-heptadiene,6-methyl-1,5-heptadiene, 6-methyl-1,7-octadiene and7-methyl-1,6-octadiene; and

trienes such as 2,3-diisopropylidene-5-norbornene. Of these,1,4-hexadiene, dicyclopentadiene and 5-ethylidene-2-norbornene arepreferably used.

In the ethylene/α-olefin/nonconjugated polyene random copolymer (B-3),it is preferred that the molar ratio of ethylene/α-olefin/nonconjugatedpolyene be in the range of 90/5/5 to 30/45/25, especially 80/10/10 to40/40/20.

The melt flow rate (MFR, measured at 230° C. under a load of 2.16 kgaccording to ASTM D 1238) of the ethylene/α-olefin/nonconjugated polyenerandom copolymer (B-3) is preferably 0.05 g/10 min or greater, stillpreferably in the range of 0.1 to 20 g/10 min.

As a specific example of the ethylene/α-olefin/nonconjugated polyenerandom copolymer (B-3), there can be mentioned ethylene/propylene/dieneterpolymer (EPDM) or the like.

The above hydrogenated block copolymer (B-4) is a product ofhydrogenation of block copolymer having a block form represented by thefollowing formula (1) or (2), wherein the hydrogenation ratio is 90 mol% or more, preferably 95 mol % or more.X(XY)n  (1)(XY)n  (2)wherein:

X represents a block polymer unit derived from a monovinyl substitutedaromatic hydrocarbon,

Y represents a block polymer unit derived from a conjugated diene, and

n is an integer of 1 to 5.

The monovinyl substituted aromatic hydrocarbon for constituting thepolymer block represented by X of the above formula (1) or (2) can be,for example, any of styrene and derivatives thereof, such as styrene,α-methylstyrene, p-methylstyrene, chlorostyrene, lower alkyl substitutedstyrenes and vinylnaphthalene. These can be used individually or incombination.

The conjugated diene for constituting the polymer block represented by Yof the above formula (1) or (2) can be, for example, any of butadiene,isoprene and chloroprene. These can be used individually or incombination. In the formulae, n is an integer of 1 to 5, preferably 1 or2.

The hydrogenated block copolymer (B-4) can be, for example, a styreneblock copolymer such as styrene/ethylene/butene/styrene block copolymer(SEBS), styrene/ethylene/propylene/styrene block copolymer (SEPS) orstyrene/ethylene/propylene block copolymer (SEP).

The block copolymer before hydrogenation can be produced by, forexample, a process wherein block copolymerization is carried out in thepresence of a lithium catalyst or Ziegler catalyst in an inert solvent.With respect to details of this process, reference can be made to, forexample, Japanese Patent Publication No. 40(1965) -23798.

Hydrogenation of the block copolymer can be performed in the presence ofknown hydrogenation catalyst in an inert solvent. With respect todetails of this hydrogenation, reference can be made to, for example,Japanese Patent Publication Nos. 42(1967)-8704, 43(1968)-6636 and46(1971) -20814.

When butadiene is used as the conjugated diene monomer, the proportionof 1,2-bond in polybutadiene block is preferably in the range of 20 to80% by weight, still preferably 30 to 60% by weight.

Commercially available block copolymers can be used as the hydrogenatedblock copolymer (B-4). For example, use can be made of KRATON G1657(trade name, produced by Shell Chemical Co., Ltd.), Septon 2004 (tradename, produced by Kuraray Co., Ltd.), or Tuftec H1052 (trade name,produced by Asahi Chemical Co., Ltd.).

The above elastomers (B) can be used individually or in combination.

Inorganic Filler (C)

The inorganic filler (C) for use in the present invention can be, forexample, any of talc, clay, calcium carbonate, mica, silicates,carbonates and glass fiber. Of these, talc and calcium carbonate arepreferred. Talc is especially preferred. The average particle size oftalc is preferably in the range of 1 to 5 μm, still preferably 1 to 3μm. These inorganic fillers (C) can be used individually or incombination.

Polypropylene Resin Composition

The polypropylene resin composition containing the above propylenehomopolymer (A1) comprises, based on the total weight of propylenehomopolymer (A1), elastomer (B) and inorganic filler (C), 30 to 80% byweight, preferably 40 to 78% by weight, still preferably 42 to 75% byweight, and optimally 45 to 70% by weight of propylene homopolymer (A1);15 to 40% by weight, preferably 15 to 35% by weight, still preferably 17to 35% by weight, and optimally 20 to 35% by weight of elastomer (B);and 5 to 30% by weight, preferably 7 to 25% by weight, still preferably8 to 23% by weight, and optimally 10 to 20% by weight of inorganicfiller (C).

The polypropylene resin composition containing the above propylene blockcopolymer (A2) comprises, based on the total weight of propylene blockcopolymer (A2) and inorganic filler (C) or based on the total weight ofpropylene block copolymer (A2), elastomer (B) and inorganic filler (C),30 to 80% by weight, preferably 40 to 78% by weight, still preferably 42to 75% by weight, and optimally 45 to 70% by weight of propylenehomopolymer segment of the propylene block copolymer (A2); 15 to 40% byweight, preferably 15 to 35% by weight, still preferably 17 to 35% byweight, and optimally 20 to 35% by weight of the sum of elastomer (B)and propylene/α-olefin random copolymer segment of the propylene blockcopolymer (A2); and 5 to 30% by weight, preferably 7 to 25% by weight,still preferably 8 to 23% by weight, and optimally 10 to 20% by weightof inorganic filler (C). It is preferred that, as aforementioned, thepropylene/α-olefin random copolymer segment (component soluble inn-decane at room temperature) of the propylene block copolymer (A2) becontained in an amount of 1 to 40% by weight, especially 3 to 30% byweight, still especially 5 to 25% by weight, and yet still especially 5to 15% by weight, based on the weight of propylene block copolymer (A2).The elastomer (B) is preferably contained in an amount of 0 to 39.7% byweight, still preferably 0 to 33.8% by weight, yet still preferably 0 to32.9% by weight, and optimally 9.5 to 32.8% by weight, based on thetotal weight of propylene block copolymer (A2), elastomer (B) andinorganic filler (C).

In cross fractionating chromatography (CFC) of these polypropylene resincompositions, it is preferred that a 100 to 135° C. eluate withorthodichlorobenzene exhibit a ratio (Mw/Mn) of weight average molecularweight (Mw) to number average molecular weight (Mn) of 1 to 3,especially 1 to 2.5. When the ratio (Mw/Mn) falls within these ranges,the occurrence of flow marks can be prevented, and an injection moldedarticle of excellent emboss transfer can be obtained. Further, theplasticization time can be shortened, so that the cooling time can beshortened to thereby enable shortening the molding cycle.

The polypropylene resin composition of the present invention obtained bymixing the above components (A), (B) and (C) at the above ratio ofamount is excellent in fluidity at the time of molding and enablesproviding a molded article which is excellent in a balance of propertiessuch as flexural modulus, impact resistance, hardness and brittletemperature. Accordingly, the polypropylene resin composition of thepresent invention can be appropriately used as a resin raw material forinjection molding, enables preventing the occurrence of flow marks, andenables obtaining an injection molded article of excellent embosstransfer. Further, with respect to the polypropylene resin compositionof the present invention, the plasticization time can be shortened, sothat the cooling time can be shortened to thereby enable shortening themolding cycle.

The components of the polypropylene resin composition of the presentinvention are not limited to the above polypropylene resin (propylenehomopolymer (A1) or propylene block copolymer (A2)), elastomer (B) andinorganic filler (C), and, according to necessity, the polypropyleneresin composition can be incorporated with additives such as a thermalstabilizer, an antistatic agent, a weathering stabilizer, a lightstabilizer, an age resister, an antioxidant, a metal salt of fatty acid,a softening agent, a dispersant, a filler, a colorant, a lubricant and apigment in an amount not detrimental to the object of the presentinvention.

As the above antioxidant, there can be added any of conventionalphenolic, sulfurous and phosphorous antioxidants.

The antioxidants can be used individually or in combination.

The amount of antioxidant to be incorporated is preferably in the rangeof 0.01 to 1 part by weight, still preferably 0.05 to 0.5 part byweight, per 100 parts by weight of the sum of polypropylene resin ((A1)or (A2)), elastomer (B) and inorganic filler (C).

As the above light stabilizer, there can be mentioned, for example, ahindered amine light stabilizer (HALS) or an ultraviolet light absorber.

The hindered amine light stabilizer can be, for example, any of:

tetrakis(1,2,2,6,6-pentamethyl-4-piperidine)-1,2,3,4-butanetetracarboxylate (molecular weight=847),

Adekastab LA-52 [molecular weight=847,tetrakis(1,2,2,6,6-pentamethyl-4-piperidine)-1,2,3,4-butanetetracarboxylate],

Adekastab LA-62 (molecular weight=about 900),

Adekastab LA-67 (molecular weight=about 900),

Adekastab LA-63 (molecular weight=about 2000),

Adekastab LA-68LD (molecular weight=about 1900), (all these Adekastabsare trade names for products of Asahi Denka Kogyo K.K.), and

Chimassorb 944 (molecular weight=72,500, trade name, produced by CibaSpecialty Chemicals).

The ultraviolet light absorber can be, for example, any of Tinuvin 326(molecular weight=316), Tinuvin 327 (molecular weight=357) and Tinuvin120 (molecular weight=438) (all these Tinuvins are trade names forproducts of Ciba Specialty Chemicals).

These light stabilizers can be used individually or in combination.

The amount of hindered amine light stabilizer or ultraviolet lightabsorber to be incorporated is preferably in the range of 0.01 to 1 partby weight, still preferably 0.1 to 0.6 part by weight, per 100 parts byweight of the sum of polypropylene resin ((A1) or (A2)), elastomer (B)and inorganic filler (C).

The above metal salt of fatty acid functions as a neutralizer for thecatalyst contained in the polypropylene resin composition and functionsas a dispersant for the filler (including inorganic filler (C)),pigment, etc. compounded in the polypropylene resin composition. Thus, amolded article having excellent properties, for example, strengthrequired for automobile inner trims can be produced from thepolypropylene resin composition incorporated with the fatty acid metalsalt.

The metal salt of fatty acid can be, for example, any of calciumstearate, magnesium stearate, lithium stearate and zinc stearate.

The amount of fatty acid metal salt to be incorporated is preferably inthe range of 0.01 to 1 part by weight, still preferably 0.05 to 0.5 partby weight, per 100 parts by weight of the sum of polypropylene resin((A1) or (A2)), elastomer (B) and inorganic filler (C). When the amountof fatty acid metal salt falls within the above ranges, not only can thefatty acid metal salt satisfactorily function as a neutralizer ordispersant but also the amount of sublimation from an molded article canbe reduced.

Known pigments can be used as the above pigment, which include, forexample, inorganic pigments such as metal oxides, sulfides and sulfates;and organic pigments such as phthalocyanine, quinacridone and benzidinepigments.

The amount of pigment to be incorporated is preferably in the range of0.01 to 10 parts by weight, still preferably 0.05 to 5 parts by weight,per 100 parts by weight of the sum of polypropylene resin ((A1) or(A2)), elastomer (B) and inorganic filler (C).

The polypropylene resin composition for use in the present invention canbe obtained by mixing or melt kneading the above polypropylene resin((A1) or (A2)), elastomer (B) and inorganic filler (C) together withadditives by the use of mixing equipments such as a Banbury mixer, asingle screw extruder, a twin screw extruder or a high-speed twin screwextruder.

Automobile Part

The automobile part of the present invention is constituted of the thusobtained polypropylene resin composition.

When the automobile part of the present invention is an injection moldedarticle, it is preferred that, at the measuring of glosses(reflectances) (angle of incidence: 90°, angle of reflection: 90° andarea where measuring is performed: 4 mmφ) of the surface of injectionmolded article at intervals of 5 mm in the direction of flow of theinjection molded article, a reflectance difference (gloss difference)between neighboring measuring points satisfy the formula:Δ reflectance difference≦0.5.

When the reflectance difference is 0.5 or less, it becomes difficult tovisually inspect flow marks on the surface of injection molded article.That is, this injection molded article has excellent appearance and issuitable for use as an automobile part of commercial value. The methodof measuring the reflectance difference (gloss difference) will bedescribed later in the Example section.

EXAMPLES

The present invention will further be illustrated below with referenceto the following Examples which in no way limit the scope of theinvention.

Example A1

[Synthesis of Metallocene Compound]

<Synthesis ofdimethylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconiumdichloride>

(1) Synthesis of 4,4′-di-t-butyldiphenylmethane

A 300 ml two-necked flask was satisfactorily purged with nitrogen. 38.4g (289 mmol) of AlCl₃ was placed in the flask, and 80 ml of CH₃NO₂ wasadded thereto to thereby dissolve the AlCl₃. Thus, solution (1) wasobtained. A 500 ml three-necked flask equipped with a dropping funneland a magnetic stirrer was satisfactorily purged with nitrogen. 25.6 g(152 mmol) of diphenylmethane and 43.8 g (199 mmol) of2,6-di-t-butyl-4-methylphenol were placed in the flask, and 80 ml ofCH₃NO₂ was added thereto to thereby dissolve them. The solution wascooled under agitation with the use of an ice bath, and the solution (1)was dropped thereinto over a period of 35 min. Thereafter, the reactionmixture was agitated at 12° C. for 1 hr. The resultant reaction mixturewas poured into 500 ml of ice water, and the reaction product wasextracted with 800 ml of hexane. The thus obtained organic layercontaining the reaction product was washed with 600 ml of a 5% aqueoussodium hydroxide solution, and dried over MgSO₄. The MgSO₄ was filteredoff, and the solvent was evaporated off. The thus obtained oil wascooled to −78° C. with the result that a solid was precipitated. Theprecipitated solid was recovered by filtration, and washed with 300 mlof ethanol. The washed solid was dried in vacuum. Thus,4,4′-di-t-butyldiphenylmethane was obtained with a yield of 18.9 g.

(2) Synthesis of 2,2′-diiodo-4,4′-di-t-butyldiphenylmethane

1.95 g (6.96 mmol) of 4,4′-di-t-butyldiphenylmethane, 0.78 g (3.48 mmol)of HIO₄, 1.55 g (6.12 mmol) of I₂ and 0.48 ml of concentrated H₂SO₄ werecharged into a 200 ml flask equipped with a magnetic stirrer. 17.5 ml ofacetic acid and 3.75 ml of water were added to the contents of theflask, and heated at 90° C. under agitation. Thus, a reaction wasconducted for 5 hr. The resultant reaction mixture was poured into 50 mlof ice water, and the reaction product was extracted with (C₂H₅)₂O. Thethus obtained organic layer containing the reaction product was washedwith 100 ml of a saturated aqueous solution of NaHSO₄. Na₂CO₃ was addedto the washed organic layer and agitated, and the Na₂CO₃ was filteredoff. The obtained organic layer was washed with 800 ml of water anddried over MgSO₄. The MgSO₄ was filtered off, and the solvent wasdistilled off. Thus, yellow oil was obtained. The yellow oil waspurified by column chromatography. As a result,2,2′-diiodo-4,4′-di-t-butyldiphenylmethane was obtained with a yield of3.21 g.

(3) Synthesis of 3,6-di-t-butylfluorene 3.21 g (6.03 mmol) of2,2′-diiodo-4,4′-di-t-butyldiphenylmethane and 2.89 g (47.0 mmol) ofcopper powder were charged into a 50 ml two-necked flask, and heated at230° C. A reaction was conducted under agitation for 5 hr. The reactionproduct was extracted with acetone, and the solvent was distilled off.Thus, reddish-brown oil was obtained. Light-yellow oil was obtained fromthe reddish-brown oil by column chromatography. Fractions containingunreacted raw materials were once more applied to the column to therebyrecover only the desired product. White solid of 3,6-di-t-butylfluorenewas obtained by recrystallization with methanol. The yield was 1.08 g.(4) Synthesis of 1-tert-butyl-3-methylcyclopentadiene

In a nitrogen atmosphere, dehydrated diethyl ether (350 ml) was added toa tert-butylmagnesium chloride/diethyl ether solution of 2.0 mol/lit.concentration (450 ml, 0.90 mol) to thereby obtain a solution. Asolution of 3-methylcyclopentenone (43.7 g, 0.45 mmol) in dehydrateddiethyl ether (150 ml) was dropped into the above solution whilemaintaining its temperature at 0° C. by cooling with ice. The mixturewas agitated at room temperature for 15 hr. A solution of ammoniumchloride (80.0 g, 1.50 mol) in water (350 ml) was dropped into thereaction mixture while maintaining its temperature at 0° C. by coolingwith ice. Water (2500 ml) was added to the obtained solution, andagitated. An organic layer containing the reaction product was separatedand washed with water. A 10% aqueous hydrochloric acid solution (82 ml)was added to the organic layer while maintaining its temperature at 0°C. by cooling with ice, and agitated at room temperature for 6 hr. Theorganic layer of the reaction mixture was separated, washed with water,a saturated aqueous solution of sodium hydrogencarbonate, water and asaturated aqueous solution of sodium chloride in sequence, and driedover anhydrous magnesium sulfate (drier). The drier was filtered off,and the solvent was distilled off from the filtrate. Thus, a liquid wasobtained. 14.6 g of light-yellow liquid(1-tert-butyl-3-methylcyclopentadiene) was obtained by vacuumdistillation (45 to 47° C./10 mmHg) of the above liquid. The analyticalvalue thereof was as follows:

¹H-NMR (at 270 MHz in CDCl₃ with reference of TMS) δ6.31+6.13+5.94+5.87(s+s+t+d, 2H), 3.04+2.95 (s+s, 2H), 2.17+2.09 (s+s, 3H), 1.27 (d, 9H).

(5) Synthesis of 3-tert-butyl-5,6,6-trimethylfulvene

In a nitrogen atmosphere, dehydrated acetone (55.2 g, 950.4 mmol) wasdropped into a solution of 1-tert-butyl-3-methylcyclopentadiene (13.0 g,95.6 mmol) in dehydrated methanol (130 ml) while maintaining itstemperature at 0° C. by cooling with ice. Further, pyrrolidine (68.0 g,956.1 mmol) was dropped thereinto, and agitated at room temperature for4 days. The obtained reaction mixture was diluted with diethyl ether(400 ml), and 400 ml of water was added. An organic layer containing thereaction product was separated and washed with a 0.5 N aqueoushydrochloric acid solution (150 ml×4), water (200 ml×3) and a saturatedaqueous solution of sodium chloride (150 ml) in sequence. The washedorganic layer was dried over anhydrous magnesium sulfate (drier). Thedrier was filtered off, and the solvent was distilled off from thefiltrate. Thus, a liquid was obtained. 10.5 g of yellow liquid(3-tert-butyl-5,6,6-trimethylfulvene) was obtained by vacuumdistillation (70 to 80° C./0.1 mmHg) of the above liquid. The analyticalvalue thereof was as follows:

¹H-NMR (at 270 MHz in CDCl₃ with reference of TMS) δ6.23 (s, 1H), 6.05(d, 1H), 2.23 (s, 3H), 2.17 (d, 6H), 1.17 (s, 9H).

(6) Synthesis of2-(3-tert-butyl-5-methylcyclopentadienyl)-2-(3,6-di-tert-butylfluorenyl)propane

In a nitrogen atmosphere, while cooling with ice, a hexane solution ofn-butyllithium (2.1 ml, 3.4 mmol) was dropped into a solution of3,6-di-tert-butylfluorene (0.9 g, 3.4 mmol) in THF (30 ml), and agitatedat room temperature for 6 hr to thereby obtain a red solution. Further,while cooling with ice, a solution of3-tert-butyl-5,6,6-trimethylfluvene (0.6 g, 3.5 mmol) in THF (15 ml) wasdropped into the red solution in a nitrogen atmosphere. The mixture wasagitated at room temperature for 12 hr, and 30 ml of water was addedthereto. An organic layer containing the reaction product was separatedby extraction with diethyl ether and dried over magnesium sulfate.Filtration was conducted, and the solvent was removed from the filtratein vacuum. Thus, a solid was obtained. This solid was subjected torecrystallization from hot methanol, thereby obtaining 1.2 g oflight-yellow solid(2-(3-tert-butyl-5-methylcyclopentadienyl)-2-(3,6-di-tert-butylfluorenyl)propane).The analytical value thereof was as follows:

¹H-NMR (at 270 MHz in CDCl₃ with reference of TMS) δ7.72 (d, 2H),7.18–7.05 (m, 4H), 6.18–5.99 (s+s, 1H), 4.32–4.18 (s+s, 1H), 3.00–2.90(s+s, 2H), 2.13–1.98 (t+s, 3H), 1.38 (s, 18H), 1.19 (s, 9H), 1.10 (d,6H).

(7) Synthesis ofdimethylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconiumdichloride

While cooling with ice, a hexane solution of n-butyllithium (3.6 ml, 5.8mmol) was dropped into a solution of2-(3-tert-butyl-5-methylcyclopentadienyl)-2-(3,6-di-tert-butylfluorenyl)propane(1.3 g, 2.8 mmol) in diethyl ether (40 ml) in a nitrogen atmosphere, andagitated at room temperature for 16 hr. The solvent was removed from thereaction mixture in vacuum, thereby obtaining a reddish-orange solid.150 ml of dichloromethane was added to the solid at −78° C. and agitatedto thereby dissolve the solid. Subsequently, the obtained solution wasadded to a suspension of zirconium tetrachloride (THF) biscomplex (1.0g, 2.7 mmol) in dichloromethane (10 ml) having been cooled to −78° C.,agitated at −78° C. for 6 hr, and at room temperature for 24 hr. Thesolvent was removed from the reaction mixture in vacuum, therebyobtaining an orange solid. This solid was subjected to extraction withtoluene, Celite filtration, removal of the solvent from the filtrate invacuum, and recrystallization from diethyl ether. Thus, there wasobtained 0.18 g of orange solid(dimethylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconiumdichloride). The analytical value thereof was as follows:

¹H-NMR (at 270 MHz in CDCl₃ with reference of TMS) δ7.98 (dd, 2H), 7.90(d, 1H), 7.69 (d, 1H), 7.32–7.25 (m, 2H), 6.01 (d, 1H), 5.66 (d, 1H),2.54 (s, 3H), 2.36 (s, 3H), 2.28 (s, 1H), 1.43 (d, 18H), 1.08 (s, 9H).

[Preparation of Methylaluminoxane Supported on Silica]

20 g of silica (trade name H-121, produced by Asahi Glass Co., Ltd.,dried at 150° C. in nitrogen for 4 hr) and 200 ml of toluene werecharged in a 500 ml reactor having satisfactorily been purged withnitrogen. Under agitation, 60 ml of methylaluminoxane (produced byAlbemarle Corporation, 10% by weight toluene solution) was droppedthereinto in a nitrogen atmosphere. Subsequently, this mixture wasreacted at 110° C. for 4 hr. The reaction system was allowed to cool tothereby precipitate a sold component. The supernatant solution wasremoved by decantation. Thereafter, the solid component was washed withtoluene three times and with hexane three times. As a result,methylaluminoxane supported on silica was obtained.

[Production of Propylene Homopolymer (A1-1)]

20 mmol, in terms of aluminum, of methylaluminoxane supported on silicawas charged in a 1000 ml two-necked flask having satisfactorily beenpurged with nitrogen, and suspended in 500 ml of heptane. A toluenesolution of 54 mg (0.088 mmol) ofdimethylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconiumdichloride was added to the suspension. Subsequently,triisobutylaluminum (80 mmol) was added thereto, and agitated for 30 minto thereby obtain a catalyst suspension.

This catalyst suspension was charged in an autoclave of 200 lit.internal volume having satisfactorily been purged with nitrogen. 40 kgof liquid propylene and 30 N lit. of hydrogen were charged thereinto,and a polymerization was effected at 70° C. under a pressure of 3.0 to3.5 MPa for 60 min. Upon the completion of polymerization, methanol wasadded thereto to thereby terminate the polymerization. Unreactedpropylene was purged off, thereby obtaining propylene homopolymer(A1-1). The propylene homopolymer (A1-1) was dried at 80° C. in vacuumfor 6 hr. The yield of propylene homopolymer (A1-1) after drying was 17kg.

The thus obtained propylene homopolymer (A1-1) had a melting point (Tm)of 158° C., an MFR (measured at 230° C. under a load of 2.16 kgaccording to ASTM D 1238) of 42 g/10 min, a weight average molecularweight (Mw) of 140,000, a number average molecular weight (Mn) of70,000, a ratio of Mw/Mn of 2.0 and an n-decane soluble content of 0.2%by weight. With respect to the stereoregularity of the propylenehomopolymer (A1-1), the mmmm fraction was 95.8%, and neither2,1-insertion nor 1,3-insertion was detected.

[Production of Polypropylene Resin Composition]

The thus obtained propylene homopolymer (A1-1), propylene/ethylenecopolymer rubber (B-1) [PER; ethylene content=41 mol % and MFR (measuredat 230° C. under a load of 2.16 kg according to ASTM D 1238)=2.0 g/10min], ethylene/1-butene copolymer rubber (B-2-a) [EBR; ethylenecontent=82 mol % and MFR (measured at 230° C. under a load of 2.16 kgaccording to ASTM D 1238)=7 g/10 min], talc (C-1) [inorganic filler,trade name K-1, produced by Hayashi Kasei], Irganox 1010 (trade name)[antioxidant, produced by Ciba Geigy], Irgafos 168 (trade name)[antioxidant, produced by Ciba Geigy], Sanol LS-770 (trade name) [HALSlight stabilizer, produced by Sankyo Co., Ltd.] and Tinuvin 120 (tradename) [ultraviolet light absorber, produced by Ciba Geigy] were blendedtogether in proportions specified in Table 1 by means of a tumblermixer. The blend was melt kneaded and pelletized by means of a twinscrew extruder.

An injection molding of the thus obtained polypropylene resincomposition into a plate (100 mm×350 mm×2 mm thick) was carried out bymeans of injection molding machine [model M-200AII-SJ-MJ, manufacturedby Meiki Seisakusho]. On the plate, flow marks were visually inspected.The plate was evaluated as “o” when flow marks were scarcely noticed, as“Δ” when flow marks were easily noticed, and as “x” when flow marks werehighly conspicuous.

Further, using the same injection molding machine and the same metalmold, the plasticization time was measured by setting the screw backpressure for 700 kg/cm².

Still further, using the same injection molding machine, a plate withits surface embossed (140 mm×360 mm×3 mm thick) was injection molded.The gloss of the surface having undergone emboss transfer was measured(the gloss of embossed surface was measured in accordance with ASTM D523wherein the angle of light incidence was 60°). The gloss was measured attwo positions, namely, position (site A) spaced by 80 mm from an endupstream of the plate center and position (site B) spaced by 80 mm froman end downstream of the plate center.

Still further, ASTM test pieces were injection molded by means ofinjection molding machine (model NN220a manufactured by NiigataSeikosho), and various properties were measured. Moreover, thepolypropylene resin composition was injection molded, and the occurrenceof flow marks was inspected by measuring the gloss difference(reflectance difference) on the surface of injection molded piece. Theresults are listed in Table 1.

The properties were measured in the following manners.

[Tensile Properties]

With respect to the tensile properties, a tensile test was performed inaccordance with ASTM D638-84. Tensile elongation was measured under thefollowing conditions.

<Testing Conditions>

test piece: No. 1 dumbbell specified in ASTM D638-84,

chuck distance: 114 mm,

temperature: 23° C., and

rate of pulling: 10 mm/min and 20 mm/min.

[Flexural Properties]

With respect to the flexural properties, the flexural modulus wasmeasured by performing a flexural test in accordance with ASTM D790under the following conditions.

<Testing Conditions>

test piece: 6.4 mm (thickness)×12.7 mm (width)×127 mm (length),

span: 100 mm,

rate of flexing: 2 mm/min, and

measuring temperature: 23° C.

[Izod Impact Strength]

The Izod impact strength was measured by performing an impact test inaccordance with ASTM D256 under the following conditions.

<Testing Conditions>

test piece: 12.7 mm (width)×6.4 mm (thickness)×64 mm (length),

notch: machining, and

measuring temperature: 23° C. and −30° C.

The injection molding conditions for obtaining test pieces used in theflow mark inspection, emboss transfer evaluation, plasticization timemeasuring and ASTM tests were as follows:

<Injection Molding Conditions>

Flow Mark Inspection:

resin temperature 230° C., metal mold temperature 40° C., rate ofinjection 25%, injection pressure 65%, and cooling time 20 sec;

Emboss Transfer Evaluation:

resin temperature 220° C., metal mold temperature 40° C., rate ofinjection 20%, injection pressure 80%, and cooling time 15 sec;

Plasticization Time Measuring:

resin temperature 210° C., metal mold temperature 40° C., rate ofinjection 30%, injection pressure 50%, and cooling time 20 sec; and

ASTM Tests:

resin temperature 210° C., metal mold temperature 40° C., rate ofinjection 40%, injection pressure 40%, and cooling time 20 sec.

[Reflectance Test]

On an injection molded plate (100 mm×350 mm×2 mm thick, one gate), thereflectances (meter: model FW-098 manufactured by Nippon Denshoku KogyoCo., Ltd., angle of incidence: 90°) were measured at intervals of 5 mmin the direction of injection flow over a length of 50 to 150 mm fromthe flow end.

Example A2

A polypropylene resin composition was produced in the same manner as inExample A1 except that the blending proportions of propylene homopolymer(A1-1), propylene/ethylene copolymer rubber (B-1), ethylene/1-butenecopolymer rubber (B-2-a) and talc (C-1) and the types and blendingproportions of additives were changed as specified in Table 2. Theobtained polypropylene resin composition was evaluated in the samemanner as in Example A1. The results are listed in Table 2.

Comparative Example A1

[Synthesis of Metallocene Compound]

<Synthesis of dimethylsilylenebis(2-methyl-4-phenylindenyl)zirconiumdichloride>

Dimethylsilylenebis(2-methyl-4-phenylindenyl)zirconium dichloride wassynthesized in the manner described in Organometallics, 13, 954 (1994).

[Production of Propylene Homopolymer (A1-2)]

Propylene homopolymer (A1-2) was produced in the same manner as inExample A1 except that 70 mg ofdimethylsilylenebis(2-methyl-4-phenylindenyl)zirconium dichloride wasused as the metallocene compound.

The yield of propylene homopolymer (A1-2) was 16.3 kg. This propylenehomopolymer (A1-2) had a melting point (Tm) of 150° C., an MFR (measuredat 230° C. under a load of 2.16 kg according to ASTM D 1238) of 40 g/10min, a ratio of Mw/Mn of 2.3 and a room temperature n-decane solublecontent of 0.6% by weight. With respect to the stereoregularity of thepropylene homopolymer (A1-2), the mmmm fraction was 95.7%, and theproportions of 2,1-insertion and 1,3-insertion were 0.80% and 0.05%,respectively. The proportion of 2,1-insertion was greater than theproportion of 1,3-insertion.

A polypropylene resin composition was produced from the obtainedpropylene homopolymer (A1-2) in the same manner as in Example A1. Theproperties thereof were evaluated, and the results are listed in Table1.

Comparative Example A2

A polypropylene resin composition was produced from the same propylenehomopolymer (A1-2) as used in Comparative Example A1 in the same manneras in Example A2. The properties thereof were evaluated, and the resultsare listed in Table 2.

Comparative Example A3

The properties of commercially available propylene homopolymer (A1-3)[trade name J108, produced by Grand Polymer] produced in the presence oftitanium supported on magnesium chloride catalyst (Ziegler Nattacatalyst) for use in this Comparative Example A3 were as follows.

The propylene homopolymer (A1-3) had a melting point (Tm) of 160° C., anMFR (measured at 230° C. under a load of 2.16 kg according to ASTM D1238) of 40 g/10 min, a ratio of Mw/Mn of 4.4 and a room temperaturen-decane soluble content of 2.0% by weight. The value of Mw/Mn ratio waslarge. With respect to the stereoregularity of the propylene homopolymer(A1-3), the mmmm fraction was 96.5%, and neither 2,1-insertion nor1,3-insertion was detected.

A polypropylene resin composition was produced from the propylenehomopolymer (A1-3) in the same manner as in Example A1. The propertiesthereof were evaluated, and the results are listed in Table 1.

Comparative Example A4

A polypropylene resin composition was produced from the same propylenehomopolymer (A1-3) as used in Comparative Example A3 in the same manneras in Example A2. The properties thereof were evaluated, and the resultsare listed in Table 2.

TABLE 1 Example A1 Comp. Ex. A1 Comp. Ex. A3 Constitution ofpolypropylene resin composition propylene homopolymer (A1-1) [wt %] 51.1— — (A1-2) [wt %] — 51.1 — (A1-3) [wt %] — — 51.1 PER (B-1) [wt %] 9.69.6 9.6 EBR (B-2-a) [wt %] 29.0 29.0 29.0 talc (C-1) [wt %] 10.3 10.310.3 Irganox 1010 [phr] 0.10 0.10 0.10 Irgafos 168 [phr] 0.10 0.10 0.10calcium stearate [phr] 0.10 0.10 0.10 Sanol LS-770 [phr] 0.10 0.10 0.10Tinuvin 120 [phr] 0.35 0.35 0.35 Property evaluation result melt flowrate [g/10 min] 25 25 25 tensile elongation [%]   500<   500<   500<flexural modulus [MPa] 1160 960 1170 Izod impact strength (23° C.) [J/m]650 650 620 Izod impact strength (−30° C.) [J/m] 140 140 110 degree ofconspicuousness of flow marks (visual ∘ ∘ Δ inspection) gloss ofembossed part (site A) [%] 2.2 2.2 2.9 gloss of embossed part (site B)[%] 2.3 2.4 3.6 plasticization time [sec] 11 11 15 Mw/Mn of CFC (100 to135° C.) eluate 2.2 2.0 5.7 Example A1 Comp. Ex. A1 Comp. Ex. A2Distance from flow end reflectance reflectance reflectance No. (mm)reflectance diff. reflectance diff. reflectance diff. 1 150 32.81 —33.10 — 33.53 — 2 145 33.00 0.19 32.99 0.11 32.91 0.62 3 140 32.88 0.1233.01 0.02 32.45 0.46 4 135 33.06 0.18 32.94 0.07 33.04 0.59 5 130 32.900.16 33.08 0.14 33.55 0.51 6 125 33.03 0.13 32.91 0.17 32.88 0.67 7 12032.95 0.08 33.04 0.13 32.43 0.45 8 115 33.10 0.15 32.99 0.05 33.03 0.609 110 32.99 0.11 32.88 0.11 33.65 0.62 10 105 32.91 0.08 33.08 0.2033.18 0.47 11 100 33.04 0.13 33.12 0.04 32.77 0.41 12 95 32.97 0.0732.95 0.17 32.52 0.25 13 90 33.11 0.14 33.01 0.06 33.07 0.55 14 85 32.910.20 32.87 0.14 33.45 0.38 15 80 33.00 0.09 33.04 0.17 32.88 0.57 16 7532.85 0.15 32.83 0.21 32.48 0.40 17 70 33.01 0.16 33.01 0.18 33.00 0.5218 65 33.04 0.03 32.91 0.10 33.55 0.55 19 60 32.87 0.17 33.07 0.16 33.080.47 20 55 33.06 0.19 32.89 0.18 32.65 0.43 21 50 32.93 0.13 33.10 0.2133.07 0.42 (Note) Unit of amount of additive: phr based on the totalweight of propylene homopolymer, talc, PER and EBR.

TABLE 2 Example A2 Comp. Ex. A2 Comp. Ex. A4 Constitution ofpolypropylene resin composition propylene homopolymer (A1-1) [wt %] 54.3— — (A1-2) [wt %] — 54.3 — (A1-3) [wt %] — — 54.3 PER (B-1) [wt %] 7.17.1 7.1 EBR (B-2-a) [wt %] 20.2 20.2 20.2 talc (C-1) [wt %] 18.4 18.418.4 Irganox 1010 [phr] 0.10 0.10 0.10 Irgafos 168 [phr] 0.10 0.10 0.10calcium stearate [phr] 0.10 0.10 0.10 Sanol LS-770 [phr] 0.15 0.15 0.15Chimassorb 944 [phr] 0.15 0.15 0.15 Property evaluation result melt flowrate [g/10 min] 31 30 28 tensile elongation [%]   500<   500<   500<flexural modulus [MPa] 2030 1780 2030 Izod impact strength (23° C.)[J/m] 320 300 280 Izod impact strength (−30° C.) [J/m] 32 30 29 degreeof conspicuousness of flow marks (visual ∘ ∘ Δ inspection) gloss ofembossed part (site A) [%] 2.5 2.6 2.9 gloss of embossed part (site B)[%] 2.4 2.5 3.1 plasticization time [sec] 12 12 16 Mw/Mn of CFC (100 to135° C.) eluate 2.2 2.1 5.8 (Note) Unit of amount of additive: phr basedon the total weight of propylene homopolymer, talc, PER and EBR.

Example B1

[Production of Propylene Block Copolymer (A2-1)]

20 mmol, in terms of aluminum, of methylaluminoxane supported on silicaas described in Example A1 was charged in a 1000 ml two-necked flaskhaving satisfactorily been purged with nitrogen, and suspended in 500 mlof heptane. A toluene solution of 54 mg (0.088 mmol) ofdimethylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconiumdichloride as described in Example A1 was added to the suspension.Subsequently, triisobutylaluminum (80 mmol) was added thereto, andagitated for 30 min to thereby obtain a catalyst suspension.

5 kg of propylene and 3 lit. of hydrogen were charged in an autoclave of20 lit. internal volume having satisfactorily been purged with nitrogen.The above catalyst suspension was added thereto, and a bulkhomopolymerization was effected at 70° C. under a pressure of 3.0 to 3.5MPa for 40 min.

Upon the completion of homopolymerization, the vent valve was opened,thereby reducing the pressure of unreacted propylene until the internalpressure of the polymerization reactor became equal to atmosphericpressure. Immediately upon the completion of pressure reduction, acopolymerization of ethylene and propylene was carried out.Specifically, a mixture of ethylene and propylene gases (25 mol %ethylene and 75 mol % propylene) was continuously fed into thepolymerization reactor while regulating the openness of the vent of thepolymerization reactor so that to the internal pressure of thepolymerization reactor became 1 MPa. Polymerization was effected at 70°C. for 60 min. A small amount of methanol was added thereto to therebyterminate the polymerization. Unreacted gas was purged off from thepolymerization reactor.

The yield of propylene block copolymer (A2-1) was 2.9 kg. This propyleneblock copolymer (A2-1) exhibited an MFR (measured at 230° C. under aload of 2.16 kg according to ASTM D 1238) of 31 g/10 min and a roomtemperature n-decane soluble content (content of propylene/ethylenerandom copolymer segment) of 11% by weight. With respect to the roomtemperature n-decane soluble component, the intrinsic viscosity [η]measured in 135° C. decalin was 2.2 dl/g, and the ethylene content was41 mol %.

The propylene homopolymer segment of the propylene block copolymer(A2-1) had a melting point (Tm) of 158° C., an MFR (measured at 230° C.under a load of 2.16 kg according to ASTM D 1238) of 42 g/10 min, aweight average molecular weight (Mw) of 140,000, a number averagemolecular weight (Mn) of 70,000, a ratio of Mw/Mn of 2.0 and a n-decanesoluble content of 0.2% by weight. With respect to the stereoregularityof the propylene homopolymer segment, the mmmm fraction was 95.8%, andneither 2,1-insertion nor 1,3-insertion was detected.

The amount, composition, molecular weight, stereoregularity, etc. ofpolymer obtained at each stage were identified in the following manner.First, the propylene block copolymer (A2-1) was treated with 150° C.n-decane for 2 hr, and cooled to room temperature. The thus precipitatedsolid component was separated by filtration. The obtained solidcomponent was regarded as the propylene homopolymer produced in thefirst stage. Further, the component obtained by concentrating thefiltrate in vacuum and drying the concentrate was regarded as then-decane soluble component. With respect to the thus obtainedcomponents, various analyses were performed in accordance with customarymethods.

[Production of Polypropylene Resin Composition]

The thus obtained propylene block copolymer (A2-1), ethylene/1-butenecopolymer rubber (B-2-b) [EBR; ethylene content=70 mol % and MFR(measured at 230° C. under a load of 2.16 kg according to ASTM D1238)=1.8 g/10 min], talc (C-1) [inorganic filler, trade name K-1,produced by Hayashi Kasei], Irganox 1010 (trade name) [antioxidant,produced by Ciba Geigy], Irgafos 168 (trade name) [antioxidant, producedby Ciba Geigy], Sanol LS-770 (trade name) [HALS light stabilizer,produced by Sankyo Co., Ltd.] and Tinuvin 120 (trade name) [ultravioletlight absorber, produced by Ciba Geigy] were blended together inproportions specified in Table 3 by means of a tumbler mixer. The blendwas melt kneaded and pelletized by means of a twin screw extruder.

An injection molding of the thus obtained polypropylene resincomposition into a plate (100 mm×350 mm×2 mm thick) was carried out bymeans of injection molding machine [model M-200AII-SJ-MJ, manufacturedby Meiki Seisakusho]. On the plate, flow marks were visually inspected.

Further, using the same injection molding machine and the same metalmold, the plasticization time was measured by setting the screw backpressure for 700 kg/cm².

Still further, using the same injection molding machine, a plate withits surface embossed (140 mm×360 mm×3 mm thick) was injection molded.The gloss of the surface having undergone emboss transfer was measured.The gloss of embossed surface was measured in accordance with ASTM D523wherein the angle of light incidence was 60°. The gloss was measured attwo positions, namely, position (site A) spaced by 80 mm from an endupstream of the plate center and position (site B) spaced by 80 mm froman end downstream of the plate center.

Still further, ASTM test pieces were injection molded by means ofinjection molding machine (model NN220a manufactured by NiigataSeikosho), and various properties were measured. The results are listedin Table 3.

The methods of measuring tensile properties, flexural properties andIzod impact strength were as described in Example A1.

Also, the injection molding conditions for flow mark inspection, embosstransfer evaluation, plasticization time measuring and ASTM testing testpieces were as described in Example A1.

Example B2

A polypropylene resin composition was produced in the same manner as inExample B1 except that the blending proportions of propylene blockcopolymer (A2-1), ethylene/1-butene copolymer rubber (B-2-b) and talc(C-1) and the types and blending proportions of additives were changedas specified in Table 4. The obtained polypropylene resin compositionwas evaluated in the same manner as in Example B1. The results arelisted in Table 4.

Comparative Example B1

[Production of Propylene Block Copolymer (A2-2)]

Propylene block copolymer (A2-2) was produced in the same manner as inExample B1 except that 70 mg ofdimethylsilylenebis(2-methyl-4-phenylindenyl)zirconium dichloride asdescribed in Example A1 was used as the metallocene compound.

The thus obtained propylene block copolymer (A2-2) exhibited an MFR(measured at 230° C. under a load of 2.16 kg according to ASTM D 1238)of 30 g/10 min and a room temperature n-decane soluble content (contentof propylene/ethylene random copolymer segment) of 11.0% by weight. Withrespect to the room temperature n-decane soluble component, theintrinsic viscosity [η] measured in 135° C. decalin was 2.2 dl/g, andthe ethylene content was 41 mol %.

The propylene homopolymer segment of the propylene block copolymer(A2-2) had a melting point (Tm) of 150° C., an MFR (measured at 230° C.under a load of 2.16 kg according to ASTM D 1238) of 40 g/10 min, aweight average molecular weight (Mw) of 141,000, a number averagemolecular weight (Mn) of 60,000, a ratio of Mw/Mn of 2.3 and a n-decanesoluble content of 0.6% by weight. With respect to the stereoregularityof the propylene homopolymer segment, the mmmm fraction was 95.9%, andthe proportions of 2,1-insertion and 1,3-insertion were 0.80% and 0.05%,respectively.

[Production of Polypropylene Resin Composition]

A polypropylene resin composition was produced from the obtainedpropylene block copolymer (A2-2) in the same manner as in Example B1.The properties thereof were evaluated, and the results are listed inTable 3.

Comparative Example B2

A polypropylene resin composition was produced from the same propyleneblock copolymer (A2-2) as used in Comparative Example B1 in the samemanner as in Example B2. The properties thereof were evaluated, and theresults are listed in Table 4.

Comparative Example B3

The properties of commercially available propylene/ethylene blockcopolymer (A2-3) [trade name J707, produced by Grand Polymer] producedin the presence of titanium supported on magnesium chloride catalyst(Ziegler Natta catalyst) for use in this Comparative Example B3 were asfollows.

The propylene/ethylene block copolymer (A2-3) exhibited an MFR (measuredat 230° C. under a load of 2.16 kg according to ASTM D 1238) of 27 g/10min and a room temperature n-decane soluble content (content ofpropylene/ethylene random copolymer segment) of 11.5% by weight. Withrespect to the room temperature n-decane soluble component, theintrinsic viscosity [η] measured in 135° C. decalin was 2.8 dl/g, andthe ethylene content was 41 mol %.

The propylene homopolymer segment of the propylene/ethylene blockcopolymer (A2-3) had a melting point (Tm) of 160° C., an MFR (measuredat 230° C. under a load of 2.16 kg according to ASTM D 1238) of 40 g/10min and a ratio of Mw/Mn of 4.4. With respect to the stereoregularity ofthe polymer of decane insoluble component, the mmmm fraction was 96.5%,and neither 2,1-insertion nor 1,3-insertion was detected.

A polypropylene resin composition was produced from the propylene blockcopolymer (A2-3) in the same manner as in Example B1. The propertiesthereof were evaluated, and the results are listed in Table 3.

Comparative Example B4

A polypropylene resin composition was produced from the same propyleneblock copolymer (A2-3) as used in Comparative Example B3 in the samemanner as in Example B2. The properties thereof were evaluated, and theresults are listed in Table 4.

TABLE 3 Example B1 Comp. Ex. B1 Comp. Ex. B3 Constitution ofpolypropylene resin composition propylene block copolymer (A2-1) [wt %]62 — — (A2-2) [wt %] — 62 — (A2-3) [wt %] — — 62 EBR (B-2-b) [wt %] 2727 27 talc (C-1) [wt %] 11 11 11 Irganox 1010 [phr] 0.10 0.10 0.10Irgafos 168 [phr] 0.10 0.10 0.10 calcium stearate [phr] 0.10 0.10 0.10Sanol LS-770 [phr] 0.10 0.10 0.10 Tinuvin 120 [phr] 0.35 0.35 0.35Property evaluation result melt flow rate [g/10 min] 25 24 23 tensileelongation [%]   500<   500<   500< flexural modulus [MPa] 1150 950 1160Izod impact strength (23° C.) [J/m] 650 650 590 Izod impact strength(−30° C.) [J/m] 150 140 110 degree of conspicuousness of flow marks(visual ∘ ∘ Δ inspection) gloss of embossed part (site A) [%] 2.2 2.22.5 gloss of embossed part (site B) [%] 2.3 2.4 3.2 plasticization time[sec] 11 11 16 Mw/Mn of CFC (100 to 135° C.) eluate 2.1 2.1 5.6 (Note 1)The contents of propylene/ethylene random copolymer segment in propyleneblock copolymers (A2-1), (A2-2) and (A2-3) were 6.82 wt %, 6.82 wt % and7.13 wt %, respectively. (Note 2) Unit of amount of additive: phr basedon the total weight of propylene block copolymer, talc and EBR.

TABLE 4 Example B2 Comp. Ex. B2 Comp. Ex. B4 Constitution ofpolypropylene resin composition propylene block copolymer (A2-1) [wt %]65 — — (A2-2) [wt %] — 65 — (A2-3) [wt %] — — 65 EBR (B-2-b) [wt %] 1515 15 talc (C-1) [wt %] 20 20 20 Irganox 1010 [phr] 0.10 0.10 0.10Irgafos 168 [phr] 0.10 0.10 0.10 calcium stearate [phr] 0.10 0.10 0.10Sanol LS-770 [phr] 0.15 0.15 0.15 Chimassorb 944 [phr] 0.15 0.15 0.15Property evaluation result melt flow rate [g/10 min] 31 30 29 tensileelongation [%]   500<   500<   500< flexural modulus [MPa] 2020 17601930 Izod impact strength (23° C.) [J/m] 320 300 290 Izod impactstrength (−30° C.) [J/m] 32 30 28 degree of conspicuousness of flowmarks (visual ∘ ∘ Δ inspection) gloss of embossed part (site A) [%] 2.52.6 2.9 gloss of embossed part (site B) [%] 2.4 2.5 2.6 plasticizationtime [sec] 12 12 18 Mw/Mn of CFC (100 to 135° C.) eluate 2.2 2.2 5.8(Note 1) The contents of propylene/ethylene random copolymer segment inpropylene block copolymers (A2-1), (A2-2) and (A2-3) were 7.15 wt %,7.15 wt % and 7.15 wt %, respectively. (Note 2) Unit of amount ofadditive: phr based on the total weight of propylene block copolymer,talc and EBR.

INDUSTRIAL APPLICATION

The present invention enables providing an automobile part (including aninjection molded article) which has an excellent balance of rigidity andimpact resistance, wherein the probability of flow marks is low and,even if flow marks occur, they are inconspicuous, and which realizesexcellent emboss transfer on the surface of molded article and isexcellent in appearance.

The polypropylene resin composition for use in the present inventioncomprises a specified propylene homopolymer (A1) or a specifiedpropylene block copolymer (A2), an elastomer (B) and an inorganic filler(C) in a specified proportion, so that the plasticization time can beshortened to thereby enable shortening the molding cycle for producingan injection molded article. Therefore, the polypropylene resincomposition enables efficiently producing an injection molded automobilepart exhibiting the above effects.

Consequently, the polypropylene resin composition of the presentinvention, by virtue of the above characteristics, can find appropriateapplication in automobile parts, for example, automotive inner trimparts such as a door trim and an instrumental panel, and automotiveouter trim parts such as a side protect mole, a bumper, a soft facia anda mud guard.

1. An automobile part comprising a polypropylene resin composition, thepolypropylene resin composition comprising a propylene block copolymer(A2) and an inorganic filler (C), the propylene block copolymer (A2)comprising propylene homopolymer segment and propylene/α-olefin randomcopolymer segment, wherein the propylene homopolymer segment of thepropylene block copolymer (A2) exhibits: (i) a melt flow rate (measuredat 230° C. under a load of 2.16 kg according to ASTM D 1238) of 20 to300 g/10 min, (ii) a proportion of position irregular units derived from2,1-insertion or 1,3-insertion of propylene monomer relative to allpropylene structural units, determined from a ³C-NMR spectrum, each of0.05% or less, and (iii) a molecular weight distribution (Mw/Mn),determined by gel permeation chromatography (GPC), of 1 to 3, andwherein, based on the total weight of the propylene block copolymer (A2)and the inorganic filler (C), in the polypropylene resin composition,the propylene homopolymer segment of the propylene block copolymer (A2)is contained in an amount of 30 to 80% by weight, the propylene/α-olefinrandom copolymer segment of the propylene block copolymer (A2) iscontained in an amount of 15 to 40% by weight, and the inorganic filler(C) is contained in an amount of 5 to 30% by weight, and in crossfractionating chromatography (CFC) of the polypropylene resincomposition, a 100 to 135° C. eluate with orthodichlorobenzene exhibitsa ratio (Mw/Mn) of weight average molecular weight (Mw) to numberaverage molecular weight (Mn) of 1 to
 3. 2. The automobile partcomprising a polypropylene resin composition as claimed in claim 1,wherein the polypropylene resin composition further contains anelastomer (B), and wherein, based on the total weight of the propyleneblock copolymer (A2), the elastomer (B) and the inorganic filler (C), inthe polypropylene resin composition, the propylene homopolymer segmentof the propylene block copolymer (A2) is contained in an amount of 30 to80% by weight, the propylene/α-olefin random copolymer segment of thepropylene block copolymer (A2) plus the elastomer (B) is contained in atotal amount of 15 to 40% by weight, and the inorganic filler (C) iscontained in an amount of 5 to 30% by weight.
 3. The automobile partcomprising a polypropylene resin composition as claimed in claim 2,wherein the elastomer (B) is at least one elastomer selected from thegroup consisting of a propylene/α-olefin random copolymer (B-1), anethylene/α-olefin random copolymer (B-2), anethylene/α-olefin/nonconjugated polyene random copolymer (B-3) and ahydrogenated block copolymer (B-4).
 4. The automobile part comprising apolypropylene resin composition as claimed in claim 2, wherein theinorganic filler (C) is talc.
 5. The automobile part comprising apolypropylene resin composition as claimed in claim 2, wherein, in crossfractionating chromatography (CFC) of the polypropylene resincomposition, a 100 to 135° C. eluate with orthodichlorobenzene exhibitsa ratio (Mw/Mn) of weight average molecular weight (Mw) to numberaverage molecular weight (Mn) of 1 to
 3. 6. The automobile partcomprising a polypropylene resin composition as claimed in claim 3,which is an injection molded article that, when reflectances (angle ofincidence: 90°, angle of reflection: 90° and area where measuring isperformed: 4 mmφ) are measured at intervals of 5 mm in a direction ofinjection flow over a length of 50 to 150 mm from a flow end, areflectance difference between neighboring measuring points satisfiesthe formula:Δ reflactance difference≦0.5.
 7. The automobile part comprising apolypropylene resin composition as claimed in claim 1, wherein theinorganic filler (C) is talc.
 8. The automobile part comprising apolypropylene resin composition as claimed in claim 1, which is aninjection molded article that, when reflectances (angle of incidence:90°, angle of reflection: 90° and area where measuring is performed: 4mmφ) are measured at intervals of 5 mm in a direction of injection flowover a length of 50 to 150 mm from a flow end, a reflectance differencebetween neighboring measuring points satisfies the formula:Δ reflectance difference≦0.5.